Hybrid vehicle control device

Abstract

To provide a control device of a hybrid vehicle, which enables a series-type hybrid vehicle to be accelerated smoothly, in accelerating the vehicle from an engine F / C operational state.SOLUTION: A control device of a hybrid vehicle comprises: an internal combustion engine; an electric motor for generating electric power that can convert power of the internal combustion engine to electric power when the internal combustion engine is in operation; a drive electric motor that supplies driving force for running to a driving wheel using electric power; and a battery that can output electric power to the electric motor for generating electric power and the drive electric motor. In starting control by which fuel is supplied to the internal combustion engine to start the hybrid vehicle at the request for accelerating the vehicle, from a motoring state where the electric motor for generating electric power is powered while stopping supply of fuel to the internal combustion engine to rotate the internal combustion engine, the control device of the hybrid vehicle calculates target rotation speed of the internal combustion engine from required driving force, and holds the rotation speed of the internal combustion engine, within a predetermined time after supply of fuel to the internal combustion engine is started, when real rotation speed of the internal combustion engine is lower than the target rotation speed.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle.

Background Art

[0002] As a system mounted on a hybrid vehicle having a plurality of power sources, for example, there is a so-called series hybrid system. The series hybrid system includes, for example, an engine, a power generation motor that generates electricity using the power of the engine, a drive motor that generates a driving force for traveling, and a battery (battery) that stores electric power supplied to the drive motor and the like. Hereinafter, a hybrid vehicle equipped with such a series hybrid system will be simply referred to as a "hybrid vehicle". Also, the electric power output will be simply referred to as "electric power" or "output".

[0003] The hybrid vehicle travels either by EV (Electric Vehicle) driving or HV (Hybrid Vehicle) driving. In EV driving, it travels using only the electric power supplied from the battery without generating electricity by the power generation motor. In HV driving, it travels using both the electric power generated by the power generation motor by the power of the engine and the electric power supplied from the battery.

[0004] And when the battery output becomes smaller than the required electric power during EV driving, the engine is started and switched to HV driving. The required electric power is, for example, the sum of the electric power required for traveling, the electric power required at the start of the engine, the margin, the loss (various energy losses), and the electric machine load.

[0005] Also, the driving patterns of the hybrid vehicle are roughly classified as follows (1) to (3). (1) "Required power < battery output": EV driving (engine stopped) (2) "Required power > battery output" and "before engine start completion": HV driving (Traveling with the electric power obtained by subtracting "the electric power required at the start of the engine" etc. from "the battery output") (3) "Required power > battery output" and "after engine startup completed": HV driving (Driving with the sum of "battery output" and "electric power generated by engine operation")

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Also, in a hybrid vehicle, there may be a case where it attempts to accelerate from a state where the engine is operating in F / C (fuel cut: fuel supply stop) (engine F / C operation state). Note that the case where the engine enters the F / C operation state is, for example, when the battery is fully charged and the power generation motor is operated to consume power.

[0008] When attempting to accelerate a hybrid vehicle from the engine F / C operation state, for example, due to the magnitude relationship between the actual rotational speed of the engine and the target rotational speed (calculated from the required driving force), or the difference in responsiveness (response speed) between the engine and the power generation motor, unnecessary acceleration and deceleration (acceleration and deceleration) may occur in the hybrid vehicle (details will be described later). That is, smooth acceleration may not be achievable.

[0009] Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for a hybrid vehicle that can achieve smooth acceleration when accelerating from the engine F / C operation state in a series hybrid vehicle.

Means for Solving the Problems

[0010] In order to solve the above problems, a control device for a hybrid vehicle according to the present invention includes an internal combustion engine that operates using fuel, a power generation motor that can convert the power of the internal combustion engine into electric power during the operation of the internal combustion engine and can start the internal combustion engine using electric power from a battery when the internal combustion engine is not operating, a drive motor that supplies a driving force for running to drive wheels using electric power, and the battery that can output electric power to the power generation motor and the drive motor. Then, in a starting control in which, while stopping the fuel supply to the internal combustion engine, the power generation motor is forced to rotate the internal combustion engine, when there is an acceleration request for the hybrid vehicle and the internal combustion engine is started by supplying fuel, a target rotational speed of the internal combustion engine is calculated from the required driving force, and when the actual rotational speed of the internal combustion engine is less than the target rotational speed, if it is within a predetermined time after the start of fuel supply to the internal combustion engine, the rotational speed of the internal combustion engine is maintained.

[0011] According to the above configuration, when accelerating from a state where the internal combustion engine is operating in F / C, at least when the above conditions are satisfied, by maintaining the rotational speed of the internal combustion engine within the predetermined time, it is possible to avoid unnecessary acceleration and deceleration of the hybrid vehicle and realize smooth acceleration.

[0012] Further, in the control device for the hybrid vehicle, a reaching rotational speed of the internal combustion engine is calculated from a driving force corresponding to an accelerator opening corresponding to an operation amount of an accelerator pedal by a driver, and when the actual rotational speed of the internal combustion engine is greater than the target rotational speed and the reaching rotational speed is greater than the actual rotational speed, if it is within the predetermined time, the rotational speed of the internal combustion engine is maintained.

[0013] According to the above configuration, based on the operation amount of the accelerator pedal by the driver, when the above conditions are satisfied, by maintaining the rotational speed of the internal combustion engine within the predetermined time, it is possible to avoid unnecessary acceleration and deceleration of the hybrid vehicle and realize smooth acceleration.

[0014] Also, in the control device of the hybrid vehicle, when the target rotational speed of the internal combustion engine is less than the actual rotational speed and the target rotational speed is greater than the target rotational speed, the rotational speed of the internal combustion engine is maintained within the predetermined time.

[0015] According to the above configuration, when the above conditions are further satisfied, by maintaining the rotational speed of the internal combustion engine within the predetermined time, unnecessary acceleration and deceleration of the hybrid vehicle can be avoided, and smooth acceleration can be realized.

Effect of the Invention

[0016] According to the present invention, when accelerating from a state where the internal combustion engine is operating in F / C, when a predetermined condition is satisfied, by maintaining the rotational speed of the internal combustion engine within the predetermined time, unnecessary acceleration and deceleration of the hybrid vehicle can be avoided, and smooth acceleration can be realized.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of a control device for a hybrid vehicle of the present invention will be described with reference to the drawings. Note that the present invention is not limited by the following embodiments. Also, in the graphs of FIGS. 2, 3, 5 to 7, the vertical relationship of the portions where a plurality of lines are close to each other does not necessarily match the magnitude relationship of the actual numerical values due to reasons such as drawing convenience.

[0019] FIG. 1 is a diagram showing an example of the main part configuration of a hybrid vehicle 1 according to an embodiment. With reference to FIG. 1, the main part configuration of the hybrid vehicle 1 in the present embodiment will be described.

[0020] The hybrid vehicle 1 is a vehicle equipped with a series-type hybrid system 2. The hybrid vehicle 1 includes drive wheels 17, an ECU (Electronic Control Unit) 31, an accelerator sensor 32, a brake switch 33, and a vehicle speed sensor 34.

[0021] The hybrid system 2 includes an engine 11, a power generation motor 12 (MG1: motor for power generation), a drive motor 13 (MG2: motor for driving), a battery 14, and a PCU (Power Control Unit) 15.

[0022] The engine 11 is, for example, an internal combustion engine such as a gasoline engine.

[0023] The power generation motor 12 can convert the power of the engine 11 into electric power during the operation of the engine 11, and can start the engine 11 using the electric power from the battery 14 when the engine 11 is not operating.

[0024] The drive motor 13 supplies a driving force for traveling to the drive wheels 17 using the electric power from the battery 14.

[0025] The battery 14 is configured to be able to output electric power to the generator motor 12 and the drive motor 13 .

[0026] The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13. The PCU 15 includes a first inverter 21, a second inverter 22, and a converter .

[0027] The first inverter 21 is an inverter device that converts the DC power from the converter 23 into AC power and converts the AC power generated by the generator motor 12 into DC power.

[0028] The second inverter 22 is an inverter device that converts the DC power from the converter 23 into AC power, and converts the AC power generated by the regenerative operation of the drive motor 13 into DC power.

[0029] The converter 23 is a converter device that boosts the DC power output from the battery 14 and that lowers the DC power output from the first inverter 21 and the second inverter 22.

[0030] When the hybrid vehicle 1 is traveling, the drive motor 13 is operated in a power running mode, and generates power.

[0031] When the hybrid vehicle 1 is traveling, and the output required of the drive motor 13 is smaller than the output of the battery 14, the hybrid vehicle 1 runs in EV (Electric Vehicle) mode. That is, in EV mode, the engine 11 is stopped, no power is generated by the generator motor 12, and the drive motor 13 is driven only by the power supplied from the battery 14 via the converter 23 and the second inverter 22.

[0032] On the other hand, when the output required by the drive motor 13 exceeds the output of the battery 14 during the running of the hybrid vehicle 1, the hybrid vehicle 1 performs HV (Hybrid Vehicle) running. That is, in HV running, the drive motor 13 is driven by both the electric power generated by the power generation motor 12 and the electric power supplied from the battery 14.

[0033] The ECU 31 is a control device that controls the hybrid system 2. The hybrid vehicle 1 is equipped with a plurality of ECUs including the ECU 31. Each ECU includes a microcomputer (microcontroller unit). The microcomputer incorporates, for example, a CPU (Central Processing Unit), a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). The plurality of ECUs are interconnected so as to enable two-way communication according to the CAN (Controller Area Network) communication protocol. Various sensors necessary for control are connected to each ECU, and the detection signals of the connected sensors are input. In addition to the detection signals input from various sensors, information necessary for control is input to each ECU from other ECUs.

[0034] In such a hybrid vehicle 1, there may be a case where it attempts to accelerate from the state where the engine 11 is operating in F / C. In such a case, for example, unnecessary acceleration and deceleration may occur in the hybrid vehicle 1 due to the magnitude relationship between the actual rotational speed and the target rotational speed of the engine, or the difference in responsiveness between the engine and the power generation motor. That is, smooth acceleration may not be achievable.

[0035] Therefore, hereinafter, a technique capable of realizing smooth acceleration when accelerating from the state where the engine 11 is operating in F / C will be described.

[0036] First, with reference to FIGS. 2 and 3, the control overview of the prior art and this embodiment will be described. FIG. 2 is a graph showing the temporal transitions of each parameter before (prior art) and after (embodiment) changes in the first control overview example. In the following, "common" means "common to the prior art and the embodiment".

[0037] Reference numerals G11 to G14 are the rotational speeds of the engine 11. Reference numeral G11 is the common target rotational speed (the target value of the rotational speed for each moment), which is calculated from the required driving force.

[0038] Reference numeral G12 is the actual rotational speed of the prior art. Reference numeral G13 is the achieved rotational speed of the embodiment. The achieved rotational speed is the rotational speed that is finally desired to be realized, which is calculated based on the operation amount of the accelerator pedal by the driver. Reference numeral G14 is the actual rotational speed of the embodiment.

[0039] Reference numeral G15 is the actual torque of the prior art of the power generation motor 12. Reference numeral G16 is the actual torque of the embodiment of the power generation motor 12.

[0040] Reference numeral G17 is the common actual torque of the engine 11.

[0041] Reference numerals G18 to G21 are the torques of the drive motor 13. Reference numeral G18 is the target torque of the prior art. Reference numeral G19 is the actual torque of the prior art.

[0042] Reference numeral G20 is the target torque of the embodiment. Reference numeral G21 is the actual torque of the embodiment.

[0043] In this example, when attempting to accelerate the hybrid vehicle 1 from a state where the engine 11 is operating in F / C mode, in the prior art, initially, since the actual rotational speed (reference G12) of the engine 11 is greater than the target rotational speed (reference G11), the target rotational speed (reference G11) calculated from the required driving force once decreases in time period T1 and then increases in time period T2. Therefore, the actual torque (reference G15) of the power generation motor 12 once decreases in time period T1 and then increases in time period T2.

[0044] As a result, the actual torque (reference G19) of the drive motor 13 once increases on the acceleration side in time period T1 and then decreases on the deceleration side in time period T2. Therefore, smooth acceleration cannot be achieved, and for example, a shock (sudden acceleration or deceleration of the hybrid vehicle 1) occurs.

[0045] On the other hand, in the embodiment, under predetermined conditions (details will be described later), the actual rotational speed (reference G14) of the engine 11 is maintained (kept) in time periods T1 and T2. As a result, the actual torque (reference G16) of the power generation motor 12 becomes constant in time periods T1 and T2. Consequently, the actual torque (reference G21) of the drive motor 13 becomes constant in time periods T1 and T2, smooth acceleration is achieved, and no shock occurs.

[0046] Next, FIG. 3 is a graph showing the temporal changes of each parameter before (prior art) and after (embodiment) the change in the second control outline example. References G31 to G41 are the same as references G11 to G21 in FIG. 2.

[0047] In this example, when attempting to accelerate the hybrid vehicle 1 from a state where the engine 11 is operating in F / C mode, in the prior art, initially, the target rotational speed (reference G31) and the actual rotational speed (reference G32) of the engine 11 increase in time period T31. However, generally, since the responsiveness of the power generation motor 12 is faster than that of the engine 11, the actual torque (reference G35) of the power generation motor 12 increases in time period T3.

[0048] As a result, the actual torque (reference sign G39) of the drive motor 13 decreases on the deceleration side during the time period T3. Therefore, smooth acceleration cannot be achieved, and for example, a shock occurs.

[0049] On the other hand, in the embodiment, under predetermined conditions (details will be described later), the actual rotational speed (reference sign G34) of the engine 11 is held (maintained) during the time period T3. As a result, the actual torque (reference sign G36) of the power generation motor 12 becomes constant during the time period T3. As a result, the actual torque (reference sign G41) of the drive motor 13 becomes constant during the time period T3, smooth acceleration is achieved, and no shock occurs.

[0050] Hereinafter, a detailed description will be given with reference to FIGS. 4 to 7. FIG. 4 is a flowchart showing the respective processes of (a) before change (prior art) and (b) after change (embodiment).

[0051] As shown in FIG. 4(a), in the process before change (prior art), first, in step S101, the engine 11 is operating in F / C (motoring state). Next, in step S102, the ECU 31 detects a depression operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver.

[0052] Next, in step S103, the ECU 31 calculates the target rotational speed of the engine 11 from the required driving force.

[0053] Next, in step S104, the ECU 31 performs FF (feed forward) control on the engine 11 toward the target rotational speed.

[0054] However, in such a process, as described with reference to FIGS. 2 and 3, smooth acceleration may not be achieved. Therefore, in the present embodiment, the process shown in FIG. 4(b) is performed.

[0055] Steps S1 and S2 in FIG. 4(b) are the same as steps S101 and S102 in FIG. 4(a).

[0056] Next, in step S3, the ECU 31 calculates the target engine speed from the required driving force, and calculates the achievable engine speed from the driving force corresponding to the accelerator opening according to the amount of operation of the accelerator pedal by the driver.

[0057] Next, in step S4, the ECU 31 determines whether the actual engine speed of the engine 11 is greater than the target engine speed. If Yes, it proceeds to step S5; if No, it proceeds to step S10.

[0058] In step S5, the ECU 31 determines whether the achievable engine speed of the engine 11 is greater than the actual engine speed. If Yes, it proceeds to step S6; if No, it proceeds to step S7.

[0059] In step S6, the ECU 31 holds (maintains) the actual engine speed of the engine 11.

[0060] In step S7, the ECU 31 determines whether the achievable engine speed of the engine 11 is greater than the target engine speed. If Yes, it proceeds to step S8; if No, it proceeds to step S9.

[0061] In step S8, the ECU 31 holds (maintains) the actual engine speed of the engine 11.

[0062] In step S9, the ECU 31 performs FF control on the engine 11 toward the target engine speed.

[0063] In step S10, the ECU 31 determines whether the elapsed time after the return from F / C is within a predetermined time. If Yes, it proceeds to step S11; if No, it proceeds to step S12. The predetermined time is set according to the difference in responsiveness between the power generation motor 12 and the engine 11 so that when accelerating the hybrid vehicle 1 from the engine F / C operating state, the start timing of the engine speed increase by the power generation motor 12 coincides with the rise of the actual torque of the engine 11.

[0064] In step S11, the ECU 31 holds (maintains) the actual rotational speed of the engine 11.

[0065] In step S12, the ECU 31 performs FF control on the engine 11 toward the target rotational speed.

[0066] Next, with reference to FIGS. 5 to 7, the first control example to the third control example will be described. FIG. 5 is an explanatory diagram of the first control example in the embodiment. In FIG. 5, it is assumed that there is a magnitude relationship of actual rotational speed < target rotational speed < arrival rotational speed for the engine 11 immediately after the accelerator pedal operation. FIG. 5(a) is the same as FIG. 4(b).

[0067] FIG. 5(b) shows a control example before the change (prior art). Reference numerals G51 to G53 represent the rotational speed of the engine 11. Reference numeral G51 represents the target rotational speed. Reference numeral G52 represents the actual rotational speed. Reference numeral G53 represents the arrival rotational speed.

[0068] Reference numeral G54 represents the actual torque of the power generation motor 12. Reference numeral G55 represents the actual torque of the engine 11.

[0069] At time t51, a depression operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the arrival rotational speed (reference numeral G53) of the engine 11 rises steeply, the target rotational speed (reference numeral G51) of the engine 11 rises, and the actual rotational speed (reference numeral G52) of the engine 11 rises following the target rotational speed (reference numeral G51).

[0070] Also, the actual torque (reference numeral G54) of the power generation motor 12 once increases after time t51 (see FIG. 3). Then, the actual torque (reference numeral G55) of the engine 11, which has lower responsiveness (slower response speed) than the power generation motor 12, starts to increase from time t52.

[0071] Among the above, the fact that the actual torque (symbol G54) of the power generation motor 12 once increases after time t51 is one of the reasons why the smooth acceleration of the hybrid vehicle 1 cannot be achieved.

[0072] On the other hand, Fig. 5(c) shows a control example after the change (embodiment). Symbols G61 to G65 are the same as symbols G51 to G55. Regarding the same matters as in Fig. 5(b), the description will be omitted as appropriate.

[0073] At time t61, the operation of stepping on the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the reaching rotational speed (symbol G63) of the engine 11 rises steeply, the target rotational speed (symbol G61) of the engine 11 rises, but the actual rotational speed (symbol G62) of the engine 11 does not change until time t62. Therefore, between times t61 and t62, the process of symbol D (step S11) is executed. Explaining with the flowchart of Fig. 5(a), it becomes No at step S4, Yes at step S10, and the actual rotational speed of the engine 11 is held at step S11.

[0074] Also, the actual rotational speed (symbol G62) of the engine 11 rises from time t62 (symbol E). Explaining with the flowchart of Fig. 5(a), it becomes No at step S10, and FF control is executed for the engine 11 toward the target rotational speed at step S12.

[0075] Then, the actual torque (symbol G64) of the power generation motor 12 does not change until time t62 after time t61, and decreases from time t62.

[0076] Also, the actual torque (symbol G65) of the engine 11 rises from time t62 after a predetermined time (symbol T4) has elapsed since time t61.

[0077] In this way, smooth acceleration of the hybrid vehicle 1 can be achieved. For this purpose, in the starting control in which the ECU 31 rotates the engine 11 by causing the power generation motor 12 to perform power running while stopping the fuel supply to the engine 11 and then starts the engine 11 by supplying fuel thereto when there is an acceleration request for the hybrid vehicle from the motoring state, the target rotational speed of the engine 11 is calculated from the required driving force, and when the actual rotational speed of the engine 11 is less than the target rotational speed, if it is within a predetermined time after the start of fuel supply to the engine 11, the rotational speed of the engine 11 is maintained.

[0078] Next, FIG. 6 is an explanatory diagram of a second control example in the embodiment. In FIG. 6, it is assumed that immediately after the accelerator pedal operation, for the engine 11, there is a magnitude relationship of target rotational speed < actual rotational speed < reaching rotational speed. Regarding the same matters as in FIG. 5, the description will be omitted as appropriate.

[0079] FIG. 6(b) is a control example before the change (prior art). Reference numerals G71 to G75 are the same as reference numerals G51 to G55 in FIG. 5(b).

[0080] At time t71, a stepping operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the reaching rotational speed (reference numeral G73) of the engine 11 rapidly increases, the target rotational speed (reference numeral G71) of the engine 11 once decreases and then increases, and the actual rotational speed (reference numeral G72) of the engine 11 follows the target rotational speed (reference numeral G71), once decreases and then increases.

[0081] Also, the actual torque (reference numeral G74) of the power generation motor 12 once decreases and then once increases after time t71. Also, the actual torque of the engine 11 increases from time t72.

[0082] Among the above, the fact that the actual torque (reference numeral G74) of the power generation motor 12 once decreases and then once increases after time t71 is one of the causes that smooth acceleration of the hybrid vehicle 1 cannot be achieved.

[0083] On the other hand, FIG. 6(c) shows a control example after the change (embodiment). Reference numerals G81 to G85 are the same as G71 to G75. For matters similar to those in FIG. 6(b), the description will be omitted as appropriate.

[0084] At time t81, a depression operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the engine speed (reference numeral G83) of the engine 11 rises steeply, and the target engine speed (reference numeral G81) of the engine 11 once decreases and then once increases, but the actual engine speed (reference numeral G82) of the engine 11 does not change until time t82. Therefore, at times t81 to t82, the respective processes of (reference numeral A (step S6), reference numeral D (step S11)) are executed.

[0085] This will be described with reference to the flowchart of FIG. 6(a). In the process leading to reference numeral A (step S6), Yes is obtained in step S4, Yes is obtained in step S5, and the actual engine speed of the engine 11 is held in step S6. Further, in the process leading to reference numeral D (step S11), No is obtained in step S4, Yes is obtained in step S10, and the actual engine speed of the engine 11 is held in step S11.

[0086] Also, the actual engine speed (reference numeral G82) of the engine 11 increases from time t82 (reference numeral E) (similar to FIG. 5).

[0087] Then, the actual torque (reference numeral G84) of the power generation motor 12 does not change from time t81 until time t82 and decreases from time t82.

[0088] Also, the actual torque (reference numeral G85) of the engine 11 increases from time t82 after a predetermined time (reference numeral T4) has elapsed from time t81.

[0089] In this way, smooth acceleration of the hybrid vehicle 1 can be achieved. For this purpose, the ECU 31 calculates the engine speed 11 from the driving force corresponding to the throttle opening according to the operation amount of the accelerator pedal by the driver, and when the actual engine speed of the engine 11 is higher than the target speed (Yes in step S4), and when the reaching speed is higher than the actual speed (Yes in step S5), if it is within a predetermined time, the engine speed of the engine 11 is maintained (reference A (step S6)).

[0090] Next, FIG. 7 is an explanatory diagram of a third control example in the embodiment. In FIG. 7, it is assumed that immediately after the accelerator pedal operation, for the engine 11, there is a magnitude relationship of target speed < actual speed < reaching speed. Regarding the same matters as in at least one of FIGS. 5 and 6, the description will be omitted as appropriate.

[0091] FIG. 7(b) shows a control example before the change (prior art). References G91 to G95 are the same as references G51 to G55 in FIG. 5(b).

[0092] At time t91, a depression operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the reaching speed of the engine 11 (reference G93) decreases, the target speed of the engine 11 (reference G91) once decreases and then increases, and the actual speed of the engine 11 (reference G92) follows the target speed (reference G91) and once decreases and then increases.

[0093] In addition, the actual torque of the power generation motor 12 (reference G94) once decreases and then once increases after time t91. Also, the actual torque of the engine 11 increases from time t92.

[0094] Among the above, the fact that the actual torque of the power generation motor 12 (reference G94) once decreases and then once increases after time t91 is one of the causes that smooth acceleration of the hybrid vehicle 1 cannot be achieved.

[0095] On the other hand, Fig. 7(c) shows a control example after the change (embodiment). Reference numerals G101 to G105 are the same as G91 to G95. Regarding matters similar to those in Fig. 7(b), the description will be omitted as appropriate.

[0096] At time t101, a depression operation of the accelerator pedal for accelerating the hybrid vehicle 1 by the driver is detected. Thereafter, the reaching rotational speed (reference numeral G103) of the engine 11 decreases, and the target rotational speed (reference numeral G101) of the engine 11 decreases and then increases. However, the actual rotational speed (reference numeral G102) of the engine 11 does not change until time t102 except for changing to follow the reaching rotational speed (reference numeral G103). Therefore, at times t101 to t102, the processes of reference numerals A (step S6), B (step S8), and D (step S11) are executed.

[0097] This will be described with reference to the flowchart of Fig. 7(a). In the process leading to reference numeral A (step S6), it becomes Yes at step S4, Yes at step S5, and the actual rotational speed of the engine 11 is held at step S6. In the process leading to reference numeral B (step S8), it becomes Yes at step S4, No at step S5, Yes at step S7, and the actual rotational speed of the engine 11 is held at step S8. Also, in the process leading to reference numeral D (step S11), it becomes No at step S4, Yes at step S10, and the actual rotational speed of the engine 11 is held at step S11.

[0098] Also, the actual torque (reference numeral G104) of the power generation motor 12 does not change except for changing in accordance with the change for following the reaching rotational speed (reference numeral G103) of the actual rotational speed (reference numeral G102) of the engine 11 from time t101 to time t102, and decreases from time t102.

[0099] Also, the actual torque (reference numeral G105) of the engine 11 increases from time t102 after a predetermined time (reference numeral T4) has elapsed since time t101.

[0100] In this way, smooth acceleration of the hybrid vehicle 1 can be achieved. For this purpose, when the engine speed of the engine 11 is less than the actual speed and the engine speed is more than the target speed within the predetermined time, the ECU 31 maintains the engine speed of the engine 11.

[0101] In this way, according to the control device of the hybrid vehicle 1 of the present embodiment, when accelerating from the state where the engine 11 is operating in F / C, when a predetermined condition is satisfied, the engine speed of the engine 11 is maintained within the predetermined time, thereby avoiding unnecessary acceleration and deceleration of the hybrid vehicle 1 and realizing smooth acceleration. Therefore, vibration and noise in the hybrid vehicle 1 can be suppressed, and the riding comfort of the passengers can be improved.

[0102] In addition, based on the operation amount of the accelerator pedal by the driver, when a predetermined condition is satisfied, the engine speed of the engine 11 is maintained within the predetermined time, thereby avoiding unnecessary acceleration and deceleration of the hybrid vehicle and realizing smooth acceleration.

[0103] In addition, by avoiding an unnecessary increase in the actual torque of the power generation motor 12 within the predetermined time, power can be saved, and the saved power can be used for the acceleration of the hybrid vehicle 1.

[0104] In addition, the program executed by the ECU 31 of the present embodiment can be recorded and provided on a recording medium readable by a computer device such as a CD (Compact Disc)-ROM (Read Only Memory), a flexible disk (FD), a CD-R (Recordable), a DVD (Digital Versatile Disk) in an installable or executable file format. Further, the program may be provided or distributed via a network such as the Internet.

[0105] Although embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0106] 1…Hybrid vehicle, 11…Engine, 12…Power generation motor, 13…Drive motor, 14…Battery, 15…PCU, 16…Drive system, 17…Drive wheels, 21…First inverter, 22…Second inverter, 23…Converter, 31…ECU, 32…Accelerator sensor, 33…Brake switch, 34…Vehicle speed sensor

Claims

1. A control device for a hybrid vehicle, comprising: an internal combustion engine operated by fuel; a power generation electric motor capable of converting the power of the internal combustion engine into electric power during operation of the internal combustion engine and starting the internal combustion engine using electric power from a battery during non-operation of the internal combustion engine; a drive electric motor that supplies a driving force for traveling to drive wheels using electric power; and the battery capable of outputting electric power to the power generation electric motor and the drive electric motor. In a starting control for starting the internal combustion engine by supplying fuel to the internal combustion engine when there is an acceleration request for the hybrid vehicle from a motoring state in which the power generation electric motor is driven in a power running mode to rotate the internal combustion engine while stopping the fuel supply to the internal combustion engine, a target rotational speed of the internal combustion engine is calculated from the required driving force. When the actual rotational speed of the internal combustion engine is less than the target rotational speed, if it is within a predetermined time after the start of fuel supply to the internal combustion engine, the actual rotational speed of the internal combustion engine is maintained. At this time, a reaching rotational speed of the internal combustion engine is calculated from a driving force corresponding to an accelerator opening according to an operation amount of an accelerator pedal by a driver. When the actual rotational speed of the internal combustion engine is more than the target rotational speed and the reaching rotational speed is more than the actual rotational speed, if it is within the predetermined time, the actual rotational speed of the internal combustion engine is maintained. A control device for a hybrid vehicle.

2. The control device for a hybrid vehicle according to claim 1, wherein when the reaching rotational speed of the internal combustion engine is less than the actual rotational speed and the reaching rotational speed is more than the target rotational speed, if it is within the predetermined time, the actual rotational speed of the internal combustion engine is maintained. ​

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