Control method and control device of series hybrid vehicle

Abstract

The vehicle (1) of the present invention is a series hybrid vehicle in which a driving motor (4) drives a driving wheel (6) using electric power generated by a generator motor (3) driven by power of an internal combustion engine (2) provided with a turbocharger (7). A control method for the vehicle (1) includes: when overflow power (EP_OVER) is at least higher than system input power (EP_SYS) and the internal combustion engine (2) is supercharged, fuel cutting of the internal combustion engine (2) is performed.

Description

Technical Field

[0001] The present invention relates to the control of a series hybrid vehicle. Background Art

[0002] JP2015-182725A discloses a hybrid vehicle that uses at least one of an internal combustion engine with a turbocharger and an electric motor as a driving source. JP5949906B discloses a hybrid vehicle that uses an internal combustion engine provided with a supercharger such as a turbocharger and an electric motor as a prime mover, and adjusts the boost pressure of the internal combustion engine by a variable boost pressure mechanism.

[0003] In an engine with a supercharger, the actual engine torque is delayed in decreasing due to the response delay of the engine torque (boost pressure), and sometimes the actual engine torque is greater than the indicated engine torque. Therefore, in a series hybrid vehicle with an engine with a supercharger, although it is necessary to reduce the power generated by the generator motor, the engine torque is sometimes delayed in decreasing due to the response delay. For example, as the foot is released from the accelerator pedal, the driving power consumption of the driving motor decreases, and the generated power needs to be reduced.

[0004] If the reduction of the engine torque is delayed, the reduction of the power generated by the generator motor driven by the engine power is also delayed. Therefore, in this case, the power generated by the generator motor cannot be within the range of the system input power of the series hybrid system.

[0005] However, the electric motor for generating electricity cannot generate electricity beyond the range of the power that can be input into the system. Therefore, in this case, due to the engine torque of the part of the power that cannot be converted into electricity within the range of the power that can be input into the system, there is a possibility that the engine rotation will surge. Summary of the invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to suppress a surge in engine rotation in a series hybrid vehicle including an engine with a supercharger.

[0007] A control method for a series hybrid vehicle according to one embodiment of the present invention is a control method for a series hybrid vehicle in which a driving motor drives a driving wheel using electric power generated by a generator motor driven by power from an engine with a supercharger, and includes: when the torque of the engine torque that exceeds the driving engine torque of the generator motor is at least higher than the driving engine torque of the generator motor corresponding to the system input power that represents the surplus of electric power received by the series hybrid system possessed by the series hybrid vehicle, and when the engine is supercharged, the engine fuel is cut off.

[0008] Another aspect of the present invention is a control method for a series hybrid vehicle, which is a control method for a series hybrid vehicle in which a driving motor drives a driving wheel using electric power generated by a generator motor driven by power from an engine with a supercharger, and includes: when the difference between a value obtained by converting the power of an internal combustion engine into electric power for the generator motor and a value obtained by converting the power of the engine that can be received by the generator motor into electric power for the generator motor is at least higher than the system input power that can be received by the series hybrid system of the series hybrid vehicle, and when the engine is supercharged, the engine fuel is cut off.

[0009] According to still another aspect of the present invention, there is provided a control device for a series hybrid vehicle corresponding to the control method for a series hybrid vehicle according to the other aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic structural diagram showing the main parts of a vehicle.

[0011] Figure 2 This is a functional block diagram showing the processing of the integrated controller.

[0012] Figure 3 This is a diagram for explaining overflow power.

[0013] Figure 4 This is a diagram illustrating the power that can be input into the system.

[0014] Figure 5 This is a functional block diagram of the main part of the processing performed by the integrated controller.

[0015] Figure 6 This is a diagram showing an example of control during F / C execution as a flowchart.

[0016] Figure 7 It is a diagram showing a modification of the determination of overflow power when F / C is executed.

[0017] Figure 8This is a diagram showing an example of control when F / C is released as a flowchart.

[0018] Fig. 9 It is a diagram showing a modification of the determination of overflow power when F / C is released.

[0019] Fig.10 This is a diagram showing an example of a timing chart.

[0020] Fig.11 It is an explanatory diagram of the spillover torque of the internal combustion engine. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] Figure 1 1 is a schematic diagram showing the main parts of a vehicle 1. The vehicle 1 includes an internal combustion engine 2, a power generation motor 3, a travel motor 4, a battery 5, drive wheels 6, a turbocharger 7, an intercooler 8, and a throttle valve 9.

[0023] The internal combustion engine 2 may be a gasoline engine or a diesel engine. The internal combustion engine 2 is an engine with a supercharger, and a turbocharger 7 is provided as a supercharger. The turbocharger 7 includes a compressor 71 and a turbine 72. The compressor 71 is provided in the intake passage 41 of the internal combustion engine 2, and the turbine 72 is provided in the exhaust passage 42 of the internal combustion engine 2. In the turbocharger 7, the turbine 72 is rotated by the exhaust gas, thereby rotating the compressor 71 via the shaft to compress the intake air.

[0024] The intake air compressed by the compressor 71 is supplied to the internal combustion engine 2 through the intercooler 8, the throttle valve 9, and the intake manifold 41a of the intake passage 41 in sequence. The intercooler 8 cools the supercharged intake air, and the throttle valve 9 adjusts the amount of intake air. The intake manifold 41a distributes the intake air to each cylinder of the internal combustion engine 2.

[0025] The generator motor 3 generates electricity by being driven by the power of the internal combustion engine 2. The travel motor 4 is driven by the power of the battery 5 to drive the drive wheels 6. The travel motor 4 also has a so-called regenerative function, which regenerates the deceleration energy as electricity by being driven to rotate with the rotation of the drive wheels 6 during deceleration. The battery 5 is charged with the power generated by the generator motor 3 and the power regenerated by the travel motor 4.

[0026] The vehicle 1 has a first power transmission path 21 and a second power transmission path 22. The first power transmission path 21 transmits power between the travel motor 4 and the drive wheel 6. The second power transmission path 22 transmits power between the internal combustion engine 2 and the power generation motor 3. The first power transmission path 21 and the second power transmission path 22 are independent power transmission paths, that is, they are power transmission paths that do not transmit power from one of the first power transmission path 21 and the second power transmission path 22 to the other.

[0027] The first power transmission path 21 is constructed to include: a first reduction gear 11 arranged on the rotating shaft 4a of the driving motor 4; a second reduction gear 12 meshing with the first reduction gear 11; a third reduction gear 13 coaxially arranged with the second reduction gear 12 and meshing with the differential gear 14; and a differential gear 14 arranged in the differential case 15.

[0028] The second power transmission path 22 is configured to include: a fourth reduction gear 16 provided on the output shaft 2a of the internal combustion engine 2; a fifth reduction gear 17 meshing with the fourth reduction gear 16; and a sixth reduction gear 18 provided on the rotating shaft 3a of the generator motor 3 and meshing with the fifth reduction gear 17.

[0029] The first power transmission path 21 and the second power transmission path 22 do not include any element for interrupting power transmission. That is, the first power transmission path 21 and the second power transmission path 22 are in a state of always transmitting power.

[0030] The vehicle 1 further includes a controller 30. The controller 30 includes an engine controller 31 for controlling the internal combustion engine 2, a generator motor controller 32 for controlling the generator motor 3, a travel motor controller 33 for controlling the travel motor 4, a battery controller 34 for controlling the battery 5, and an integrated controller 35 for integrating the control of the vehicle 1.

[0031] The engine controller 31 is composed of a microcomputer having a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The same is true for other controllers. The engine controller 31, the power generation motor controller 32, the driving motor controller 33, and the battery controller 34 are connected to each other through a CAN-compliant bus via an integrated controller 35 so as to be communicable with each other.

[0032] The controller 30 is input with signals from various sensors and switches, including: ICEThe rotation speed sensor 81 for detecting the accelerator opening APO indicating the amount of depression of the accelerator pedal, the water temperature sensor 83 for detecting the water temperature THW of the internal combustion engine 2, and the oil temperature T OIL An oil temperature sensor 84 for detecting a vehicle speed VSP, a vehicle speed sensor 85 for detecting a vehicle speed VSP, a pressure sensor 86 for detecting an intake pressure P, and a current and voltage sensor 87 for detecting a current I and an applied voltage V of an auxiliary machine that consumes power, such as an air conditioning device or an electric power steering device. These signals are input to the integrated controller 35 directly or via other controllers such as the engine controller 31. The pressure sensor 86 is provided in the intake passage 41 at a position where the boost pressure of the internal combustion engine 2 can be detected, and in the present embodiment, is provided in the intake manifold 41a. The current and voltage sensor 87 may be composed of a plurality of sensors, or may include a plurality of sensors provided for each auxiliary machine. Signals such as the rotational speed, torque, and SOC (state of charge) as a parameter representing the state of charge of the battery 5 are also input to the controller 30 from the power generation motor 3, the travel motor 4, and the battery 5.

[0033] The vehicle 1 is a series hybrid vehicle in which a driving motor 4 drives a driving wheel 6 using electric power generated by a generator motor 3 driven by power of an internal combustion engine 2. The controller 30 constitutes a series hybrid system together with auxiliary machines in addition to the internal combustion engine 2, the generator motor 3, the driving motor 4, and the battery 5.

[0034] As described above, the internal combustion engine 2 is an engine with a supercharger. In such an internal combustion engine 2, as the torque TQ ICE The response delay of (boost pressure) is such that the actual torque TQ of the internal combustion engine 2 ICE _A ratio indicated torque TQ ICE Therefore, in the vehicle 1 equipped with the internal combustion engine 2, although it is necessary to reduce the generated power, the torque TQ may be reduced due to a response delay. ICE For example, this corresponds to a situation where the driving power consumption of the running motor 4 decreases as the foot is released from the accelerator pedal (the foot is released from the accelerator pedal), thereby generating a need to reduce the generated power.

[0035] When the torque TQ ICE When the decrease of EP_SYS is delayed, the decrease of the power generated by the generator motor 3 driven by the power of the internal combustion engine 2 is also delayed. Therefore, in this case, the power generated by the generator motor 3 does not converge to the range of the system input power EP_SYS of the series hybrid system.

[0036] However, the generator motor 3 cannot generate power in a range exceeding the system input power EP_SYS. Therefore, in this case, there is a concern that the torque TQ that cannot be converted into power due to power generation within the range of the system input power EP_SYS ICE , which produces a surge in engine rotation.

[0037] In particular, when the accelerator pedal is released, the driving power consumption of the running motor 4 decreases as usual, while the power generated by the generator motor 3 is difficult to decrease. Therefore, the system input power EP_SYS decreases and tends to surge.

[0038] In addition, in this embodiment, there is no mechanism for rapidly reducing the boost pressure, such as a return valve that returns the compressed intake air from the downstream side of the compressor 71 to the upstream side. Therefore, it is not possible to use such a mechanism to reduce the boost pressure, and the indicated torque TQ ICE _T reduction, torque TQ ICE The response delay is likely to become larger.

[0039] In view of such circumstances, in the present embodiment, the integrated controller 35 is configured as follows.

[0040] Figure 2 3 is a functional block diagram showing the processing of the integrated controller 35. The integrated controller 35 includes a drive target calculation unit 351, a target power calculation unit 352, an ENG mode determination unit 353, and a target ENG operating point calculation unit 354.

[0041] The drive target calculation unit 351 calculates the target torque TQ of the traction motor 4. MG _T. Target torque TQ MG _T is based on the actual rotation speed N of the driving motor 4 MG _A and target driving force. Target torque TQ MG _T is calculated as follows.

[0042] That is, first, the target driving force is calculated based on the vehicle speed VSP and the accelerator opening APO. The target driving force is preset based on the vehicle speed VSP and the accelerator opening APO. The calculated target driving force is converted into the torque of the rotating shaft 4a of the driving motor 4 by using the gear ratio set on the first power transmission path 21 and the tire diameter of the driving wheel 6, and the converted torque is calculated as the target torque TQ MG _T. Then, the actual speed N MG _A is used to calculate the maximum torque of the driving motor 4 in absolute value, and the maximum torque of the driving motor 4 in absolute value is used as the target torque TQ MGThe target driving force is a negative value, i.e., the target regenerative power, when the traction motor 4 is regenerating. The calculated target torque TQ MG _T is input to the driving motor 4.

[0043] The driving target calculation unit 351 further calculates the vehicle required power EP V _T. Vehicle requests power EP V _T is the requested power of the vehicle 1 corresponding to the target driving force of the traction motor 4, and is calculated based on the target driving force of the traction motor 4. The calculated vehicle requested power EP V _T is input to the target power calculation unit 352 and the target ENG operation point calculation unit 354.

[0044] The target power calculation unit 352 calculates the target power based on the vehicle required power EP. V _T, calculate the target power EP for power generation or discharge of the power generation motor 3 GEN _T. During power generation, the internal combustion engine 2 drives the power generation motor 3. When the positive vehicle required power EP is input V _T, the upper limit charging power is used as the upper limit to calculate the target generated power. The upper limit discharge power is used to limit the vehicle required power EP which is absolutely negative. V The upper limit charge power and the upper limit discharge power are input to the target power calculation unit 352 from the battery controller 34 together with the SOC. The SOC is used for calculation of the system input power EP_SYS described later.

[0045] Furthermore, the target power calculation unit 352 receives the intake pressure P, the oil temperature T of the internal combustion engine 2, and ... OIL And the actual speed N ICE The suction pressure P is used for processing in the surge advance detection unit 352a described later. The oil temperature T OIL and actual speed N ICE _A is used for calculation of overflow power EP_OVER described below.

[0046] Figure 3 : This is an explanatory diagram of overflow power EP_OVER. The power that can be generated corresponding to the power of the internal combustion engine 2 (hereinafter, also referred to as the generateable power) is a value obtained by converting the power of the internal combustion engine 2 into the power of the generator motor 3. The part of the generateable power that does not converge to the range of the system input power EP_SYS cannot be generated by the generator motor 3. The generateable power is composed of the power corresponding to the receivable power of the generator motor 3 and the overflow power EP_OVER.

[0047] The electric power corresponding to the power that can be received by the generator motor 3 refers to the value obtained by converting the power of the internal combustion engine 2 that can be received by the generator motor 3 into the electric power of the generator motor 3, and is obtained by converting the power of the internal combustion engine 2 that can be received by the generator motor 3 to the maximum extent. This electric power is composed of the generated electric power and the loss electric power of the generator motor 3. The overflow electric power EP_OVER refers to the part of the electric power that can be generated that exceeds the electric power corresponding to the power that can be received by the generator motor 3. Therefore, the overflow electric power EP_OVER is composed of the difference between the electric power that can be generated and the electric power corresponding to the power that can be received by the generator motor 3.

[0048] For example, when the torque TQ of the internal combustion engine 2 ICE The actual torque TQ ICE _A becomes the specific indicated torque TQ ICE When the power EP_OVER is large, the generated power exceeds the power corresponding to the power that the generator motor 3 can receive. This overflow power EP_OVER means to overcome the friction torque of the internal combustion engine 2 and the speed N of the internal combustion engine 2. ICE The friction torque is calculated based on the oil temperature T. OIL And the actual speed N ICE _A is pre-set based on the oil temperature T OIL And the actual speed N ICE _A operation. You can also use water temperature THW instead of oil temperature T OIL The inertia torque is calculated by the relationship of inertia torque = angular acceleration × inertia moment. The angular acceleration can be calculated by subtracting the rotation speed N obtained in each calculation cycle. ICE The difference between the current value and the previous value of is divided by the calculation period. As the inertia moment, the inertia moment of the power transmission system constituting the second power transmission path 22 is used.

[0049] return Figure 2 , the actual torque TQ is further input from the generator motor 3 to the target power calculation unit 352 GEN _A and actual speed N GEN _A. Actual torque TQ GEN _A and actual speed N GEN _A is used for calculation of the power generated by the generator motor 3. The calculated power generated by the generator motor 3 is used for calculation of the system inputtable power EP_SYS as described below.

[0050] Figure 4: This is an explanatory diagram of the system input power EP_SYS. The system input power EP_SYS is a value indicating the residual amount of power received by the series hybrid system, and is obtained by subtracting the power generated by the generator motor 3 from the sum of the input power of the battery 5, the auxiliary machine power consumption, and the driving power consumption. The input power of the battery 5 is calculated based on the SOC. The auxiliary machine power consumption is calculated based on the signal from the current and voltage sensor 87. As the driving power consumption, the vehicle request power EP is used. V _T.

[0051] from Figure 2 The target power calculation unit 352 shown in the figure inputs the target power EP to the ENG mode determination unit 353 and the target ENG operation point calculation unit 354. GEN _T. The ENG mode determination unit 353 determines the target power EP based on the target power EP. GEN _T determines the operation mode of the internal combustion engine 2. The operation mode includes a driving force request power generation mode which is a power generation mode for generating power according to a vehicle driving force request. When it is determined that the operation mode is the driving force request power generation mode, a signal of the mode flag is input to the target ENG operation point calculation unit 354 as a signal of the vehicle driving force request flag.

[0052] The target ENG operating point calculation unit 354 calculates the target power EP GEN _T corresponds to the target operating point of the internal combustion engine 2. The target operating point can be determined based on the target power EP GEN _T is preset. When a positive target power EP is input GEN _T is the target generated power, the target speed N of the internal combustion engine 2 corresponding to the target generated power is calculated as the target operating point. ICE _T and indicated torque TQ ICE _T. Calculated target speed N ICE _T is input to the generator motor 3 and used for controlling the generator motor 3. The target speed N ICE _T variable speed ratio converted into target speed N of the generator motor 3 GEN The upper and lower torque limit command values ​​of the generator motor 3 are also input to the generator motor 3. The command value is based on the vehicle required power EP V _T is preset. The calculated indicated torque TQ ICE _T is input to the engine controller 31 and used for controlling the internal combustion engine 2. A signal of an F / C (fuel cut) flag is also input to the engine controller 31. The F / C flag is set as follows.

[0053] Figure 5This is a functional block diagram of the main parts of the processing performed by the integrated controller 35. The target power calculation unit 352 has a surge advance detection unit 352a and an F / C unnecessary judgment unit 352b. The target ENG operation point calculation unit 354 has: an F / C flag setting unit 354a, an elapsed time judgment unit 354b and a setting clear indication unit 354c. Various signals shown in the figure including the intake pressure P are input to the surge advance detection unit 352a. These signals are also input to the F / C unnecessary judgment unit 352b. In addition to the intake pressure P, the various signals shown in the figure are used for the calculation of overflow power EP_OVER, the calculation of system input power EP_SYS, and the calculation of vehicle request power EP V _T restrictions.

[0054] The surge detection unit 352a detects the surge of the engine rotation in advance. The pre-detection condition is that the overflow power EP_OVER is greater than the system input power EP_SYS and the internal combustion engine 2 is supercharged. When the intake pressure P is greater than the specified value P1, it is determined that the internal combustion engine 2 is supercharged. The specified value P1 can be pre-set to a value greater than the atmospheric pressure. When the pre-detection condition is met, the on signal of the pre-detection flag is input to the F / C flag setting unit 354a.

[0055] The F / C unnecessary determination unit 352b determines whether fuel cut is unnecessary. The F / C unnecessary condition is that the overflow power EP_OVER is smaller than the system input power EP_SYS and the internal combustion engine 2 is not supercharged. When the intake pressure P is less than the specified value P2, it is determined that the internal combustion engine 2 is not supercharged. The specified value P2 can be pre-set to a value less than the atmospheric pressure. When the F / C unnecessary condition is met, the F / C unnecessary signal is input to the setting clear instruction unit 354c.

[0056] When the on signal of the pre-detection flag is input, the F / C flag setting unit 354a sets the F / C flag to on. The on signal of the F / C flag is input to the engine controller 31, thereby cutting off the fuel of the internal combustion engine 2. The on signal of the F / C flag is also input to the elapsed time determination unit 354b.

[0057] The elapsed time determination unit 354b determines whether a predetermined time has elapsed since the start of fuel cut based on the on signal of the F / C flag. The predetermined time is a timeout time for fuel cut, which is set in advance through experiments, etc. If the predetermined time has elapsed since the start of fuel cut, an elapsed completion signal is input to the setting clear instruction unit 354c.

[0058] The setting clear instruction unit 354c inputs a setting clear signal of the F / C flag to the F / C flag setting unit 354a when an F / C unnecessary signal, an ON signal of the vehicle driving force request flag, or a completion signal is input. The ON signal of the vehicle driving force request flag is input from the ENG mode determination unit 353 to the setting clear instruction unit 354c.

[0059] When the setting clear signal is input, the F / C flag setting unit 354a clears the setting of the F / C flag. As a result, the F / C flag is turned off. When the F / C flag on signal is no longer input, the engine controller 31 releases the fuel cutoff of the internal combustion engine 2. When the F / C flag on signal is no longer input, the elapsed time determination unit 354b stops time measurement and clears the measured time.

[0060] Figure 6 This is a flowchart showing an example of control performed by the controller 30 when the F / C is executed. The process of step S1 may be performed by the integrated controller 35 , and the process of step S2 may be performed by the engine controller 31 .

[0061] In step S1, the controller 30 determines whether the overflow power EP_OVER is greater than the system input power EP_SYS and whether the internal combustion engine 2 is supercharged. In other words, it determines whether the above-mentioned pre-detection condition is satisfied. If the determination is negative in step S1, the process returns to step S1, and if the determination is positive in step S1, the process proceeds to step S2.

[0062] In step S2, the controller 30 executes a fuel cut of the internal combustion engine 2. ICE The response delay caused by the engine rotation surge, torque TQ ICE and speed N ICE The fuel pressure is reduced in advance and quickly. As a result, the engine speed surge is suppressed. In addition, since the internal combustion engine 2 does not transmit power to the drive wheels 6, even if the fuel is cut off, it will not affect the behavior of the vehicle 1. After step S2, the processing is temporarily terminated.

[0063] In step S1 , the overflow power EP_OVER may be determined as follows.

[0064] Figure 7 FIG. 4 is a diagram showing a modified example of determining overflow power EP_OVER during F / C execution. Figure 7As shown, the determination threshold D1 is the sum of the system input power EP_SYS and the specified value α. The specified value α is a value for making the timing of detecting the surge of engine rotation in advance match the appropriate timing, and is set in advance through experiments or the like. According to such a determination, the surge of engine rotation can be more appropriately suppressed by fuel cut. In this case, since the overflow power EP_OVER increases and the system input power EP_SYS decreases, the overflow power EP_OVER becomes larger than the determination threshold D1.

[0065] Figure 8 This is a flowchart showing an example of control performed by the controller 30 when the F / C is released. The processing of step S11 to step S13 may be performed by the integrated controller 35 , and the processing of step S14 may be performed by the engine controller 31 .

[0066] In step S11, the controller 30 determines whether the overflow power EP_OVER is smaller than the system inputtable power EP_SYS and whether the internal combustion engine 2 is not supercharged. In other words, it determines whether the above-mentioned F / C unnecessary condition is satisfied.

[0067] If the determination in step S11 is affirmative, the process proceeds to step S14, and the controller 30 cancels the fuel cut. ICE The fuel cut-off is released to prevent the engine speed from soaring due to the response delay. After step S14, the process is temporarily terminated.

[0068] In the case of a negative determination in step S11, the process proceeds to step S12, and the controller 30 determines whether there is a vehicle driving force request. Whether there is a vehicle driving force request can be determined based on the vehicle driving force request flag signal. If the determination is positive in step S12, the process proceeds to step S14, and the fuel cutoff is released. As a result, the driving of the driving motor 4 is restarted, and the power generation operation of the internal combustion engine 2 is also restarted.

[0069] If a negative determination is made in step S12, the process proceeds to step S13, where the controller 30 determines whether a predetermined time has elapsed since the start of the fuel cut. The predetermined time is based on the actual torque TQ of the internal combustion engine 2. ICE _A relative to indicated torque TQ ICE _T response delay. This is because if the actual torque TQ has passed ICE _A is sufficient to follow the indicated torque TQ ICE _T, the overflow power EP_OVER is likely to be smaller than the system input power EP_SYS. If a negative determination is made in step S13, the process returns to step S11.

[0070] If an affirmative determination is made in step S13, the process proceeds to step S14, where the fuel cut is cancelled. This can prevent the fuel cut from being excessively continued.

[0071] In step S11 , it may be determined whether or not at least one of the following two conditions holds true: the overflow power EP_OVER is smaller than the system inputtable power EP_SYS; and the internal combustion engine 2 is not supercharged.

[0072] When the previous condition is satisfied, the series hybrid system has a surplus of electric power to be received. Therefore, in this case, from the viewpoint of the surplus of electric power to be received, the power generation operation of the internal combustion engine 2 can be restarted as soon as possible.

[0073] When the latter condition is met, the torque TQ of the internal combustion engine 2 ICE To some extent, the overflow power EP_OVER is likely to be smaller than the system input power EP_SYS. In addition, if the internal combustion engine 2 is not supercharged, the actual torque TQ of the internal combustion engine 2 is ICE _A relative to indicated torque TQ ICE _T generates only a response delay within the allowable range, so the overflow power EP_OVER is likely to be smaller than the system input power EP_SYS. Therefore, in this case, by ICE The internal combustion engine 2 is restarted to generate electricity before the torque TQ is greatly reduced. ICE responsiveness.

[0074] In step S12, it is also possible to further determine whether the power of the power generating motor 3 is needed as the power source of the driving motor 4. In this case, if the power of the power generating motor 3 is needed, by entering step S14, the power generation operation of the internal combustion engine 2 can be restarted in response to the necessity of restarting power generation.

[0075] In step S11 , the overflow power EP_OVER may be determined as follows.

[0076] Fig. 9 : is a diagram showing a modified example of the determination of overflow power EP_OVER when F / C is released. The release threshold D2 is the size of the difference between the system input power EP_SYS and the specified value β. The specified value β is a value used to make the time of releasing the fuel cut suitable for the appropriate time, and is set in advance through experiments, etc. According to such a determination, it is possible to release the unnecessary fuel cut more appropriately. In this case, since the overflow power EP_OVER decreases and the system input power EP_SYS increases, the overflow power EP_OVER becomes smaller than the release threshold D2.

[0077] The controller 30 is programmed to Figure 6, Figure 8 The processing of the flowchart shown in FIG. 1 is thus configured to include a control unit. The controller 30 as the control unit is programmed to satisfy Figure 2 , Figure 5 Functional block diagram shown.

[0078] Fig.10 1 is a diagram showing an example of a timing chart corresponding to the control performed by the controller 30 . Fig.10 Indicates that it is used when F / C is executed and released, and in the judgment of overflow power EP_OVER. Figure 7 , Fig. 9 The actual speed N of the internal combustion engine 2 represented by two dashed lines is shown in FIG. ICE _A and target speed N ICE _T represents the case of a comparative example. The comparative example represents the case where fuel cut is not performed.

[0079] At time T1, during high-speed driving, the driver releases his foot from the accelerator pedal while the internal combustion engine 2 is operating at a high output such as maximum output. As a result, the accelerator opening APO starts to decrease, and the torque TQ of the driving motor 4 is MG The accelerator opening APO becomes zero immediately after time T1. Torque TQ MG As your foot leaves the accelerator pedal, the torque gradually decreases. MG When the accelerator pedal is released, the system input power EP_SYS decreases accordingly. On the other hand, the intake pressure P does not immediately start to decrease when the foot is released from the accelerator pedal, thereby generating the actual torque TQ of the internal combustion engine 2. ICE _A relative to indicated torque TQ ICE _T's response delay.

[0080] At time T2, the intake pressure P is higher than the predetermined value P1. That is, the internal combustion engine 2 is supercharged. Furthermore, at time T2, the overflow power EP_OVER becomes larger than the determination threshold value D1 due to the decrease in the system inputtable power EP_SYS. As a result, the pre-detection flag is turned on.

[0081] At time T3, the F / C flag turns on in response to the pre-detection flag turning on. Therefore, the fuel cut starts and the speed N ICE From time T3, the power generated by the generator motor 3 increases with the rotation speed N ICE The decrease in EP_SYS will reduce the system input power EP_SYS accordingly.

[0082] At time T4, the intake pressure P becomes lower than the specified value P2. That is, the internal combustion engine 2 is not supercharged. Furthermore, at time T4, the overflow power EP_OVER caused by the increase in the system input power EP_SYS is smaller than the release threshold D2. As a result, the F / C unnecessary condition is satisfied, and the pre-detection flag becomes OFF.

[0083] At time T5, the F / C flag turns OFF as the F / C unnecessary condition is satisfied. Therefore, the power generation operation of the internal combustion engine 2 is restarted, and the speed N ICE The system can input power EP_SYS as the speed N ICE decreases with the increase of .

[0084] In the case of the comparative example, the fuel cut is not performed at the time T3. Therefore, in this case, the torque TQ of the internal combustion engine 2 which cannot be converted into electric power by the electric motor 3 for generating electricity is ICE , which produces a surge in engine rotation.

[0085] In the present embodiment, by performing fuel cut at time T3, the torque TQ of the internal combustion engine 2 is ICE As a result, the speed N ICE It also drops quickly, suppressing the surge in engine rotation.

[0086] Next, the main effects of this embodiment will be described.

[0087] The control method of the vehicle 1 includes cutting off the fuel of the internal combustion engine 2 when the overflow power EP_OVER is at least higher than the system inputtable power EP_SYS and the internal combustion engine 2 is supercharged.

[0088] According to this method, by detecting the torque TQ of the internal combustion engine 2 in advance, ICE The fuel of the internal combustion engine 2 is cut off to prevent the engine speed from rising due to the response delay, so that the speed N to be increased can be quickly reduced. ICE Therefore, according to such a method, the internal combustion engine 2 provided with the turbocharger 7 can suppress the surge in engine rotation.

[0089] In addition, according to such a method, since there is no need to provide a mechanism for rapidly reducing the boost pressure, the complexity of the series hybrid system can be avoided. Furthermore, according to such a method, since the boost pressure is not limited, when the internal combustion engine 2 is running at a high output during high-speed driving, the power generated by the generator motor 3 is limited, thereby also avoiding the situation where the vehicle driving force is insufficient.

[0090] The method of controlling the vehicle 1 further includes releasing the fuel cut when at least one of the conditions that the overflow power EP_OVER is lower than the system inputtable power EP_SYS and the internal combustion engine 2 is not supercharged is satisfied.

[0091] According to the former condition, the power generation operation of the internal combustion engine 2 can be restarted as soon as possible from the viewpoint of the surplus amount of power received. According to the latter condition, the torque TQ of the internal combustion engine 2 is ensured. ICE Based on the two conditions, it is possible to ensure that the torque TQ is maintained while taking into account the margin of power reception. ICE Responsive manner to restart power generation as soon as possible.

[0092] The control method of vehicle 1 further includes canceling the fuel cut when there is a vehicle driving force request. According to such a method, the power generation operation of internal combustion engine 2 can be restarted in response to the restart of driving of traveling motor 4, so the reduction of SOC of battery 5 can be suppressed.

[0093] In this case, the fuel cutoff can be released when the power of the generator motor 3 is needed as the power source of the travel motor 4. Thus, when the drive of the travel motor 4 is restarted, the power generation operation of the internal combustion engine 2 can be restarted according to the necessity of restarting power generation.

[0094] The control method of the vehicle 1 further includes calculating overflow power EP_OVER based on the sum of the inertia torque of the internal combustion engine 2 and the friction torque of the internal combustion engine 2. According to such a method, the overflow power EP_OVER can be appropriately calculated, so the surge in engine rotation can be appropriately suppressed.

[0095] The control method of the vehicle 1, if the torque TQ of the internal combustion engine 2 is used ICE To express it, it can be expressed as follows.

[0096] Fig.11 2 is an explanatory diagram of the spillover torque of the internal combustion engine 2. The driving engine torque of the electric motor 3 for generating electricity is the torque TQ consumed by driving the electric motor 3 for generating electricity. ICE , which is composed of the generator torque of the generator motor 3 and the loss torque. The generator torque of the generator motor 3 is the torque TQ consumed by the power generation. ICE The loss torque is the torque that is not consumed in power generation and becomes a loss in the driving engine torque. ICE The overflow torque is composed of the driving engine torque and the overflow torque. Therefore, the overflow torque is the torque TQ that exceeds the driving engine torque of the generator motor 3. ICEOn the other hand, the driving engine torque of the generator motor 3 corresponding to the system input power EP_SYS represents the torque TQ that can be converted into electric power through the power generation of the generator motor 3. ICE .

[0097] Therefore, the control method of vehicle 1 can also be said to include: when the overflow torque is at least higher than the driving engine torque of the generator motor 3 corresponding to the system input power EP_SYS and the internal combustion engine 2 is supercharged, the fuel of the internal combustion engine 2 is cut off. In this case, the surge in engine rotation can also be suppressed.

[0098] As mentioned above, although the embodiment of the present invention has been described, the above embodiment merely shows a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiment.

[0099] For example, a supercharger other than the turbocharger 7 may be provided in the internal combustion engine 2. In addition, the control method of the vehicle 1 may be implemented by, for example, a single controller.

Claims

1. A control method for a series hybrid vehicle, the series hybrid vehicle having a controller for controlling, wherein a driving motor for driving a driving wheel is driven by a driving motor using electric power generated by a power generating motor driven by a power of an engine with a supercharger, wherein: The control method comprises: performing a preliminary test including determining whether the remaining power is greater than the power that can be input into the system; Taking the result of executing the prior detection as a condition, when the torque of the engine that exceeds the driving engine torque of the generator motor is at least higher than the driving engine torque of the generator motor corresponding to the system input power representing the surplus of power received by the series hybrid system of the series hybrid vehicle and the engine is supercharged, the fuel cut-off of the engine is performed as the control.

2. A control method for a series hybrid vehicle, the series hybrid vehicle having a controller for controlling, wherein a driving motor for driving a driving wheel is driven by a driving motor using electric power generated by a power generating motor driven by a power of an engine with a supercharger, wherein: The control method comprises: performing a preliminary test including determining whether the remaining power is greater than the power that can be input into the system; Taking the result of executing the preliminary detection as a condition, when the difference between the value obtained by converting the power of the engine into the electric power of the generator motor and the value obtained by converting the power of the engine that can be received by the generator motor into the electric power of the generator motor is at least higher than the system input power representing the surplus of electric power received by the series hybrid system of the series hybrid vehicle and the engine is supercharged, the fuel cut-off of the engine is performed as the control.

3. The control method of a series hybrid vehicle according to claim 2, wherein: The control further includes canceling the fuel cut when at least one of the difference is lower than the system inputtable power and the engine is not supercharged.

4. The control method for a series hybrid vehicle according to any one of claims 1 to 3, wherein: The method further includes cancelling the fuel cut as the control when there is a vehicle driving force request.

5. The control method of a series hybrid vehicle according to claim 4, wherein: When the electric power of the electric power generating motor is required as the electric power source of the electric power generating motor, the fuel cut is canceled as the control.

6. The control method of a series hybrid vehicle according to claim 2, wherein: The method further includes: the controller calculating the difference by using the sum of the inertia torque of the engine and the friction torque of the engine.

7. A control device for a series hybrid vehicle, wherein the series hybrid vehicle drives driving wheels with a running motor using electric power generated by a generator motor driven by power of an engine with a supercharger, wherein: The control device comprises: a pre-detection unit configured to determine whether the remaining power is greater than the power that can be input into the system; A control unit that communicates with the pre-detection unit and cuts off fuel to the engine when a difference between a value obtained by converting the power of the engine into the electric power of the generator motor and a value obtained by converting the power of the engine that can be received by the generator motor into the electric power of the generator motor is at least higher than the system input power representing the surplus of electric power received by the series hybrid system of the series hybrid vehicle and the engine is supercharged.

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