Control device of hybrid vehicle

Abstract

To provide a control device of a hybrid vehicle which enhances fuel economy of an engine without incurring deterioration of power performance and is capable of preventing deterioration of exhaust emission.SOLUTION: A control device of a hybrid vehicle is configured so as to control an engine 1 on the basis of a fully open operation line which connects an operating point where the engine 1 outputs maximum torque under a condition that accelerator opening is maximum and a non fully open operation line which connects an operating point where exhaust condition of the engine 1 is improved in comparison with the fully open operation line and to operate a hybrid vehicle Ve by selecting either CD mode or CS mode and at the same time to inhibit use of the fully open operation line when selecting the CD mode and to set request driving force corresponding to condition that accelerator opening is maximum on the basis of composite torque which sums engine torque which is determined on the basis of the non fully open operation line and motor torque capable of being output according to allowable discharge power of a battery 5 and to control driving force (step 2).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle equipped with an engine (internal combustion engine) and a motor as a driving force source. [Background technology]

[0002] Patent Document 1 describes a control device for a hybrid vehicle that selects one of a plurality of control modes, including a CS (Charge Sustaining) mode that suppresses the decrease in the amount of stored electricity in the battery and a CD (Charge Depleting) mode that consumes the power of the battery, to control the running of the vehicle. When the engine speed is within a range below a preset value, the control device for a hybrid vehicle described in Patent Document 1 switches the engine operating line in accordance with the selected control mode so that the engine operating line when the CD mode is selected is located on the side of lower engine torque than the engine operating line when the CS mode is selected.

[0003] Furthermore, Patent Document 2 describes a control device for a hybrid vehicle that is intended to improve fuel efficiency in a CD mode in a hybrid vehicle that selects either a CD mode or a CS mode to run in the CD mode. The control device for a hybrid vehicle described in Patent Document 2 selects either a CD mode that consumes the SOC of the battery or a CS mode that maintains the SOC of the battery at a predetermined level to run the vehicle. When the CD mode is selected, the control device controls the maximum value of the vehicle driving force to be smaller than when the CS mode is selected. The maximum value of the vehicle driving force when the CD mode is selected is set so that the torque of the electric motor does not exceed a limit torque that is set based on the efficiency of the electric motor.

[0004] Patent Document 3 describes a control device for a hybrid vehicle that aims to obtain a large driving force even when the motor output is restricted. The control device for a hybrid vehicle described in Patent Document 3 runs the hybrid vehicle while charging the battery when the required driving force for the hybrid vehicle is greater than the driving force that can be output when the motor generator output is at its maximum and the battery is not charged (maximum driving force without battery charging). Patent Document 3 also describes a control example that calculates a target engine torque based on the required driving force, the maximum driving force without battery charging, and the maximum driving force with battery charging (driving force that can be output when the battery is charged), as well as a WOT (Wide Open Throttle) operating line. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-75534 A [Patent Document 2] JP 2016-16689 A [Patent Document 3] JP 2019-199194 A Summary of the Invention [Problem to be solved by the invention]

[0006] A hybrid vehicle (HEV) equipped with an engine and a motor (motor generator) as a driving force source can drive the motor with power supplied from a battery, generate driving force with the output of the motor, and run (motor running or EV running), and can also make the motor function as a generator to charge the battery. In particular, so-called plug-in hybrid vehicles (PHEVs) that can charge the battery from an external power source are equipped with a battery with a larger capacity than normal HEVs, and basically run in EV mode until the battery's SOC falls below a predetermined level. In such PHEVs, the CD mode and CS mode described in the above Patent Documents 1 and 2 are usually set, and either the CD mode or the CS mode is selected depending on the battery's SOC (State Of Charge).

[0007] On the other hand, the engine installed as a driving force source of the HEV or PHEV is controlled based on a full throttle operation line (WOT operation line) and a fuel efficiency priority operation line, which are set as shown in FIG. 1. The full throttle operation line or the fuel efficiency priority operation line is selected according to the magnitude of the required driving force, and the engine torque and engine speed are controlled based on the selected operation line. Therefore, when the CD mode is set in the PHEV as described above, for example, when a large driving force is required in a state where the accelerator pedal is fully depressed, the engine output is added together with the motor output in the CD mode to generate a large driving force corresponding to the required driving force. In such a case, in the conventional control, the full throttle operation line is selected and the engine is controlled in a maximum output state in order to prioritize power over the fuel efficiency of the engine. When the engine is controlled based on the full throttle operation line, the fuel efficiency and exhaust emissions (exhaust gas properties and emissions) of the engine deteriorate compared to when the engine is controlled based on the fuel efficiency priority operation line. When the fuel efficiency priority operation line is selected for a large driving request such as when the accelerator is fully opened, the obtained driving force is insufficient, and the power performance of the hybrid vehicle is reduced.

[0008] This invention has been devised in light of the above technical problems, and aims to provide a control device for a hybrid vehicle that can improve engine fuel efficiency without reducing power performance, and prevent deterioration of exhaust emissions. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a control device for a hybrid vehicle which is equipped with an engine and a motor as a driving force source that outputs a driving torque for generating a driving force, and which includes a battery which exchanges electric power with the motor, and which is capable of running by selectively setting at least a first control mode in which the motor is driven by supplying electric power from the battery, and a second control mode in which electric power is not supplied from the battery to the motor, and which controls the driving force based on a required driving force which is set corresponding to a vehicle speed and an accelerator opening, and which includes a controller which controls the hybrid vehicle, and which controls at least a fully opened state which connects an operating point where the engine outputs a maximum torque when the accelerator opening is at a maximum, and a control mode which controls the driving force based on a required driving force which is set corresponding to a vehicle speed and an accelerator opening. The engine is controlled based on an operating line and a non-full throttle operating line connecting operating points where the exhaust condition of the engine is improved compared to the full throttle operating line, and the hybrid vehicle is driven by selecting either the first control mode or the second control mode, and when the first control mode is selected, the use of the full throttle operating line is prohibited (i.e., operation of the engine based on the full throttle operating line is prohibited), and the required driving force corresponding to the state where the accelerator opening is at its maximum is set based on a composite torque obtained by summing the output torque of the engine determined based on the non-full throttle operating line and the output torque of the motor that can be output in accordance with the discharge allowable power of the battery at that time, thereby controlling the driving force.

[0010] In addition, the controller in this invention may be configured, when the first control mode is selected, to determine a predetermined condition under which the exhaust condition may deteriorate, and when it is determined that the exhaust condition may deteriorate, to prohibit the use of the full-throttle operating line, and to set the required driving force corresponding to the state in which the accelerator opening is at its maximum based on the composite torque, and to control the driving force.

[0011] In addition, the non-full throttle operating line in this invention may include a fuel efficiency prioritized operating line that connects operating points where the exhaust condition is improved and the fuel efficiency of the engine is improved compared to the full throttle operating line, or where the fuel efficiency of the engine is optimized, and the composite torque in this invention may include a fuel efficiency prioritized torque that is the sum of the output torque of the engine determined based on the fuel efficiency prioritized operating line and the output torque of the motor that can be output in accordance with the discharge allowable power of the battery.

[0012] In addition, the non-full throttle operating line in this invention may include an intermediate operating line connecting operating points where the exhaust condition improves and the fuel efficiency improves compared to the full throttle operating line, and where the output torque of the engine increases compared to the fuel efficiency priority operating line, and the composite torque in this invention may include an intermediate torque that is the sum of the output torque of the engine determined based on the intermediate operating line and the output torque of the motor that can be output according to the discharge allowable power of the battery, and the controller in this invention may be configured to prohibit the use of the full throttle operating line when the first control mode is selected or when it is determined that there is a possibility that the exhaust condition will deteriorate, and to set the required driving force corresponding to the state where the accelerator opening is at its maximum based on the intermediate torque, and control the driving force.

[0013] Furthermore, the first control mode in this invention may include a CD mode in which the stored power of the battery is consumed by the motor, and the second control mode in this invention may include a CS mode in which the amount of stored power in the battery is maintained at a predetermined level or a decrease in the amount of stored power in the battery is suppressed, and the controller in this invention may be configured to prohibit use of the full throttle operating line when the CD mode is selected, and to set the required driving force corresponding to the state in which the accelerator opening is at its maximum based on the composite torque, and to control the driving force.

[0014] In addition, the controller in this invention may be configured to determine, when the CD mode is selected, predetermined conditions that may cause the exhaust condition to deteriorate, and if it determines that there is a possibility that the exhaust condition will deteriorate, to prohibit the use of the full-throttle operating line, and to set the required driving force corresponding to the state in which the accelerator opening is at its maximum based on the composite torque, and to control the driving force.

[0015] In addition, the non-full throttle operating line in this invention may include a fuel efficiency prioritized operating line that connects operating points where the exhaust condition is improved and the fuel efficiency of the engine is improved compared to the full throttle operating line, and the composite torque in this invention may include a fuel efficiency prioritized torque that is the sum of the output torque of the engine determined based on the fuel efficiency prioritized operating line and the output torque of the motor that can be output in accordance with the discharge allowable power of the battery.

[0016] The non-full throttle operating line in this invention may include an intermediate operating line connecting operating points where the exhaust condition improves and the fuel efficiency improves compared to the full throttle operating line, and where the output torque of the engine increases compared to the fuel efficiency priority operating line, and the composite torque in this invention may include an intermediate torque that is the sum of the output torque of the engine determined based on the intermediate operating line and the output torque of the motor that can be output in accordance with the discharge allowable power of the battery, and the controller in this invention may be configured to prohibit the use of the full throttle operating line when the CD mode is selected or when it is determined that there is a possibility that the exhaust condition will deteriorate, and to set the required driving force corresponding to the state where the accelerator opening is at its maximum based on the intermediate torque, and control the driving force. Effect of the Invention

[0017] The hybrid vehicle of the present invention includes an engine and a motor as a driving force source. A battery is connected to the motor via a power supply device such as an inverter or converter. Therefore, the motor is driven by the power supplied from the battery to output torque. It is also possible to charge the battery with electricity generated by the motor. The engine is operated based on a full throttle operating line that is an operating state in which the maximum torque is output corresponding to the maximum or full throttle accelerator opening, and a non-full throttle operating line that is an operating state in which the exhaust state of the engine is improved, that is, the amount of exhaust gas discharged is reduced and the properties and components of the exhaust are improved, compared with the case where the engine is operated based on the full throttle operating line. The hybrid vehicle of the present invention runs by selectively setting a first control mode or CD mode and a second control mode or CS mode.

[0018] In the hybrid vehicle configured as described above, when the first control mode or the CD mode is selected and the vehicle is driven, in the state where the accelerator opening is at its maximum, that is, when the driving demand amount by the driver's operation is at its maximum, the engine is operated and the output torque of the engine is added to generate a driving force in order to obtain a large driving force corresponding to the maximum driving demand. In this case, in the conventional control, the engine is operated based on the above-mentioned full throttle operation line, with the idea of ​​obtaining the maximum torque of the engine to respond to the large driving demand. By adding the maximum torque of the engine to the output torque of the motor in the first control mode or the CD mode, a larger driving force (for example, the maximum driving force of the hybrid vehicle) can be generated, and good vehicle dynamic performance can be obtained. However, when the engine is operated on the full throttle operation line, the maximum torque of the engine can be obtained, but the exhaust state of the engine is deteriorated compared to when the engine is operated on a non-full throttle operation line that does not output the maximum torque, such as a fuel efficiency priority operation line. For example, the amount of exhaust emission increases, and exhaust components such as CO increase. In addition, the fuel efficiency of the engine is also deteriorated. On the other hand, in the control device for a hybrid vehicle of the present invention, when the first control mode or the CD mode is selected, the operation of the engine based on the full throttle operating line is prohibited. At the same time, the required driving force (i.e., the target driving force in the driving force control) corresponding to the large driving demand at which the accelerator opening is maximized is set based on a composite torque that combines the engine torque when the engine is operated on a non-full throttle operating line such as the fuel efficiency priority operating line or the intermediate operating line, and the motor torque that can be output according to the battery state at that time. Therefore, even when a large driving force at which the accelerator opening is maximized is required, the use of the full throttle operating line is avoided, and the deterioration of the exhaust state of the engine is suppressed. In addition, since the maximum torque of the motor that can be output at that time is added to the engine torque based on the non-full throttle operating line, it is possible to appropriately respond to a large driving demand. In other words, the power performance of the hybrid vehicle can be ensured.

[0019] Therefore, according to the control device for a hybrid vehicle of the present invention, it is possible to improve the fuel efficiency of the engine without causing a decrease in the power performance of the hybrid vehicle, and also to prevent a deterioration in the exhaust emissions of the engine. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing an image of a full-throttle operating line (WOT operating line) and a fuel-economy-priority operating line used in conventional engine control. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration and control system of a hybrid vehicle that is an object of control in the present invention. [Diagram 3] FIG. 3 is a flowchart for explaining an example of control (basic control example) executed by the control device for a hybrid vehicle of the present invention. [Figure 4] FIG. 4 is a diagram showing an image of a required driving force map used for driving force control of a hybrid vehicle of the present invention. [Diagram 5] FIG. 5 is a flowchart for explaining another example of control executed by the control device for a hybrid vehicle of the present invention (a control example in which control for determining the exhaust state of the engine is added). [Figure 6] FIG. 6 is a diagram showing an image of a full throttle operating line, a fuel efficiency priority operating line, and an intermediate operating line used for engine control and driving force control of the hybrid vehicle of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings. Note that the following embodiment is merely an example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0022] The vehicle to be controlled in the embodiment of the present invention is a hybrid vehicle equipped with at least an engine and a motor as a driving force source. The motor is connected to a battery so as to be able to receive and transmit electric power. The battery supplies electric power to drive the motor, which outputs torque. It is also possible to charge the battery with electricity generated by the motor. Therefore, the vehicle may be a so-called motor-generator that combines the functions of a prime mover and a generator. Alternatively, the vehicle may be equipped with a plurality of motors, including a motor that mainly functions as a prime mover and a motor that mainly functions as a generator. In the embodiment described later, an example is shown in which two motors (a first motor 2 and a second motor 3) are mounted. FIG. 2 shows an outline of the configuration of a hybrid vehicle (hereinafter, vehicle) Ve to be controlled in the embodiment of the present invention.

[0023] 2 includes an engine (ENG) 1, a first motor (MG) 2, a second motor (MG) 3, a power split mechanism (GEAR) 4, and a battery (BAT) 5. The vehicle Ve also includes a detection unit 6 and a controller (ECU) 7 for executing various controls.

[0024] The engine 1 is an internal combustion engine, such as a gasoline engine or a diesel engine, that obtains power by burning fuel. The engine 1 is configured so that the output adjustment and operating state such as starting and stopping are electrically controlled. In the case of a gasoline engine, the opening of the throttle valve, the amount of fuel supplied or injected, the timing of fuel injection, the start and stop of ignition, the ignition timing, etc. are electrically controlled.

[0025] The first motor 2 is connected to the engine 1 and drive wheels 10 (described later) via a power split mechanism 4 (described later) so as to be capable of transmitting power. The first motor 2 is also electrically connected to a battery 5 (described later) so as to be able to receive and transmit electric power. The first motor 2 also functions as a generator that generates electric power when driven by the torque output by the engine 1. In other words, the first motor 2 is a so-called motor generator that has a power generating function, and is configured, for example, by a permanent magnet synchronous motor or an induction motor.

[0026] The second motor 3 is connected to drive wheels 10 via, for example, a differential gear 8 and a drive shaft 9 so as to be capable of transmitting power. The second motor 3 is also electrically connected to a battery 5, which will be described later, so as to be able to receive and transmit electric power. The second motor 3 at least functions as an electric motor that is driven by a supply of electric power to output torque. The second motor 3 also functions as a generator that generates electric power by receiving torque from the outside and being driven. That is, the second motor 3 is a so-called motor generator that has a power generating function, similar to the first motor 2 described above, and is configured by, for example, a permanent magnet type synchronous motor or an induction motor.

[0027] The power split mechanism 4 is connected to the engine 1 and the first motor 2 so as to be capable of transmitting power, and transmits the output torque (engine torque) of the engine 1 and the output torque (motor torque) of the first motor 2 to the drive wheels 10. In the example shown in Fig. 2, the power split mechanism 4 is disposed coaxially with the first motor 2 and the engine 1 and adjacent to the first motor 2. The power split mechanism 4 is configured, for example, by utilizing the differential rotation function of a planetary gear mechanism (not shown).

[0028] The battery 5 is, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery. The battery 5 is electrically connected to the first motor 2 and the second motor 3 via an inverter (INV) 11 or the like so as to be able to exchange electric power with each other. The battery 5 is therefore charged by the electric power generated by the first motor 2 and stores the electricity. The battery 5 also supplies electric power to the second motor 3, causing the second motor 3 to generate a drive torque.

[0029] Furthermore, in the example shown in FIG. 2, the battery 5 is configured to be capable of being charged by power supplied from an external power source 12 of the vehicle Ve. As described above, the vehicle Ve generates electricity using the engine 1 and the first motor 2, and is driven by the output of the second motor 3 described later. Therefore, in the example shown in FIG. 2, the vehicle Ve is a so-called split-type "plug-in hybrid vehicle (PHEV)" equipped with a power split mechanism 4. However, the vehicle Ve to be controlled in the embodiment of the present invention is not limited to the above-mentioned split-type PHEV. For example, the vehicle Ve may be an "electric vehicle with a range extender" capable of being charged by power supplied from the above-mentioned external power source 12. The vehicle Ve may also be a normal "hybrid vehicle (HEV)" that is not equipped with a charging function from the external power source 12. Alternatively, the vehicle Ve may be a parallel or series type HEV or PHEV other than the above-mentioned split type.

[0030] The detection unit 6 is a device or apparatus for acquiring various data and information required for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, and an input / output interface. In particular, the detection unit 6 in the embodiment of the present invention detects data for controlling the engine 1, the first motor 2, and the second motor 3. For example, the detection unit 6 has various sensors and devices such as an engine speed sensor 6a for detecting the rotation speed of the engine 1, a motor speed sensor 6b for detecting the rotation speed of the first motor 2, a motor speed sensor 6c for detecting the rotation speed of the second motor 3, a SOC sensor 6d for detecting the state of charge (SOC) of the battery 5, a battery current sensor 6e for detecting the current value of the battery 5, and a battery temperature sensor 6f for detecting the temperature of the battery 5. The detection unit 6 is electrically connected to a controller 7 described later, and outputs an electric signal corresponding to the detection value or the calculation value of the various sensors, devices, and the like as described above to the controller 7 as detection data.

[0031] The controller 7 is an electronic control device mainly composed of, for example, a microcomputer, and mainly controls the operations of the engine 1, the first motor 2, and the second motor 3. Various data detected or calculated by the above-mentioned detection unit 6 is input to the controller 7. The controller 7 performs calculations using the various input data and pre-stored data, calculation formulas, etc. Then, the controller 7 is configured to output the calculation results as control command signals and control the operations of the engine 1, the first motor 2, and the second motor 3, etc., as described above.

[0032] In particular, the controller 7 in the embodiment of the present invention selectively sets at least a first control mode in which the first motor 2 and the second motor 3 (mainly the second motor 3) are driven by supplying electric power from the battery 5, and a second control mode in which electric power is not supplied from the battery 5 to the first motor 2 and the second motor 3, to run the vehicle Ve (battery control). In addition, at that time, the controller 7 controls the driving force of the vehicle Ve based on the accelerator opening (i.e., the driving demand amount by the driver's operation) and the required driving force determined from the vehicle speed (driving force control). Furthermore, the controller 7 controls the operation of the engine 1 based on at least a full throttle operation line (or a WOT operation line) connecting the operating points at which the engine 1 outputs the maximum torque when the accelerator opening is at its maximum (i.e., the accelerator opening is 100%), and a non-full throttle operation line connecting the operating points at which the exhaust state of the engine 1 is improved compared to the full throttle operation line (engine control). Although only one controller 7 is shown in FIG. 2, a plurality of controllers 7 may be provided for each device or equipment to be controlled, or for each control content.

[0033] In the embodiment of the present invention, the controller 7 of the vehicle Ve is configured to execute, for example, the control shown in the flowchart of FIG. 3 in order to appropriately execute the battery control, driving force control, and engine control as described above.

[0034] The control shown in the flowchart of Fig. 3 is executed, for example, when a main switch or a power switch (not shown) of the vehicle Ve is turned ON. First, in step S1, it is determined whether the control mode that determines the control content of the vehicle Ve and the battery 5 is set to a CD (Charge Depleting) mode or a first control mode. The CD mode is a control mode in which the electric power stored in the battery 5 is consumed by the motors 2 and 3, and is included in the "first control mode" in the embodiment of the present invention. Therefore, in the CD mode, the first motor 2 or the second motor 3 is driven by power supplied from the battery 5.

[0035] In the battery control in the embodiment of the present invention, for example, either the CD mode (or the first control mode) or the CS (Charge Sustaining) mode (or the second control mode) is selected and set according to the SOC (State Of Charge) of the battery 5. The CS mode is a control mode that maintains the charge amount of the battery 5 at a predetermined level or suppresses a decrease in the charge amount of the battery 5, and is included in the "second control mode" in the embodiment of the present invention. Therefore, in the CS mode, power is not supplied from the battery 5 to the first motor 2 and the second motor 3.

[0036] The CD mode and the CS mode are switched depending on, for example, the SOC of the battery 5. The PHEV as shown in FIG. 2 above basically runs with the output torque of the second motor 3 using the stored power of the battery 5 charged by the external power source 12. Therefore, during normal times when the SOC of the battery 5 is sufficient, the CD mode is selected and power is supplied from the battery 5 to drive the second motor 3. Then, when the SOC of the battery 5 drops to a predetermined level, the mode transitions to the CS mode, and the amount of stored power in the battery 5 is controlled to be maintained at the predetermined level.

[0037] If the control mode of the vehicle Ve and the battery 5 is not the CD mode (first control mode), i.e., is set to the CS mode (second control mode), and therefore the answer to step S1 is "No," the routine shown in the flowchart of FIG. 3 is temporarily terminated without executing any further control.

[0038] On the other hand, if the control mode of the vehicle Ve and the battery 5 is set to the CD mode (first control mode) and therefore "Yes" is determined in step S1, the process proceeds to step S2.

[0039] In step S2, the use of the full throttle operation line (or the WOT operation line) is prohibited. At the same time, as shown in Fig. 4, in the driving force control in the embodiment of the present invention, the required driving force corresponding to the state in which the accelerator opening is maximum (100%) is set based on a composite torque (or a fuel efficiency priority torque) that is a sum of the engine torque determined based on the non-full throttle operation line (or the fuel efficiency priority operation line) and the motor torque that can be output according to the discharge allowable power (or the dischargeable power) of the battery 5. In addition, in the engine control in the embodiment of the present invention, the operation of the engine 1 is controlled based on the full throttle operation line and the fuel efficiency priority operation line, as shown in Fig. 1 described above.

[0040] The full throttle operating line is an operating line that connects operating points where the engine 1 outputs maximum torque when the driving demand from the driver's operation is at its maximum, i.e., when the accelerator pedal is at its maximum (100%). In engine control, the operating point of the engine 1 is a control target value of the engine 1 that is determined, for example, from the engine torque and engine speed. By controlling the engine 1 based on the full throttle operating line, the engine 1 is brought into an operating state where it outputs maximum torque. Therefore, the vehicle Ve is brought into a state where it is possible to generate maximum driving force corresponding to the maximum or full throttle accelerator pedal opening.

[0041] On the other hand, the fuel efficiency priority operation line is an operation line that connects operating points where the exhaust state of the engine 1 is improved and the fuel efficiency of the engine 1 is improved or the fuel efficiency of the engine 1 is optimized, as compared with the above-mentioned full throttle operation line. That is, the fuel efficiency priority operation line is an operation line that connects operating points where the exhaust state of the engine 1, such as the displacement and exhaust components, is improved, as compared with the full throttle operation line, and is included in the non-full throttle operation line in the embodiment of the present invention. By controlling the engine 1 based on the non-full throttle operation line, it is possible to reduce the amount of exhaust gas emitted by the engine 1 and to reduce exhaust components such as CO, as compared with the case where the engine 1 is controlled based on the full throttle operation line. In addition, by controlling the engine 1 based on the fuel efficiency priority operation line, it is possible to reduce the amount of exhaust gas emitted by the engine 1 and to reduce exhaust components such as CO, as compared with the case where the engine 1 is controlled based on the full throttle operation line. Furthermore, it is possible to improve the fuel efficiency of the engine 1.

[0042] As described above, when the CD mode is set in the PHEV shown in FIG. 2, if a large driving force is required such that the accelerator opening is maximized, the output of the engine 1 is added to the output of the second motor 3 in the CD mode to generate a large driving force corresponding to the required driving force. In such a case, in the conventional control, the full throttle operation line as described above is selected and the engine 1 is controlled in a maximum output state in order to prioritize power over the fuel efficiency of the engine 1. Since the exhaust temperature becomes high in the maximum output state of the engine 1, the fuel injection amount may be increased (so-called OTP increase, OT increase) in order to reduce the exhaust temperature and protect the catalyst. Therefore, when the engine 1 is controlled based on the full throttle operation line, the fuel efficiency and exhaust emissions (exhaust characteristics and emissions) of the engine 1 are deteriorated compared to when the engine 1 is controlled based on the non-full throttle operation line or the fuel efficiency priority operation line. If the fuel efficiency priority operation line or the non-full throttle operation line is selected for a large driving request such that the accelerator opening is maximized, the obtained driving force is insufficient, and the power performance of the vehicle Ve is deteriorated.

[0043] Therefore, in the control device for the hybrid vehicle Ve in the embodiment of the present invention, as shown in the flowchart of FIG. 3 and FIG. 4, when the control mode of the vehicle Ve and the battery 5 is set to the CD mode (first control mode), the operation of the engine 1 based on the full throttle operation line is prohibited. At the same time, the required driving force corresponding to a large driving request with the accelerator opening at the maximum is set based on a fuel efficiency priority torque (or a composite torque) that combines the engine torque when the engine 1 is operated on the fuel efficiency priority operation line (or the non-full throttle operation line) and the motor torque that can be output according to the state of the battery 5 at that time. By prohibiting the operation of the engine 1 based on the full throttle operation line, the deterioration of the exhaust state of the engine 1 is suppressed. At the same time, the required driving force is set based on the fuel efficiency priority torque (composite torque) that combines the maximum motor torque that can be output at that time in addition to the engine torque, so that an appropriate driving force corresponding to the driving request can be obtained.

[0044] As described above, in step S2, the use of the full-throttle operating line is prohibited and the required driving force is set based on the fuel efficiency priority torque (composite torque), and then the routine shown in the flowchart of Figure 3 is temporarily terminated.

[0045] Another control example executed by the control device for a hybrid vehicle in the embodiment of the present invention is shown in the flowchart of Fig. 5. In the control shown in the flowchart of Fig. 5, the control of step S11 is added to the control example shown in the flowchart of Fig. 4 above.

[0046] In the flowchart of Figure 5, if the control mode of the vehicle Ve and the battery 5 is set to the CD mode (first control mode) and the result is "Yes" in step S1, then in step S11 it is determined whether or not a predetermined condition that may cause the exhaust condition of the engine 1 to deteriorate is met.

[0047] Examples of predetermined conditions that may cause the exhaust state of the engine 1 to deteriorate include the following: (1) The intake temperature of engine 1 is equal to or higher than a predetermined temperature. (2) The exhaust temperature of the engine 1 is equal to or higher than a predetermined temperature. (3) The temperature of the engine 1 cooling water is equal to or higher than a predetermined temperature. (4) The estimated temperature of the catalyst (not shown) is equal to or higher than a predetermined temperature. (5) The altitude of the current location of the vehicle Ve is equal to or higher than a predetermined altitude. (6) The use of fuel with properties that may cause the exhaust gas to deteriorate. When at least one of these predetermined conditions is met, it is determined that the exhaust state of the engine 1 may deteriorate.

[0048] If none of the above-mentioned predetermined conditions are met and it is determined that there is no possibility of the exhaust condition of the engine 1 deteriorating, and therefore the answer is "No" in this step S11, the routine shown in the flowchart of FIG. 5 is temporarily terminated without executing any further control.

[0049] On the other hand, if at least one of the above-mentioned predetermined conditions is satisfied and it is determined that there is a possibility that the exhaust state of the engine 1 will deteriorate, and thus the determination is "Yes" in step S11, the process proceeds to step S2, and the same control as before is executed. That is, the use of the full-throttle operating line is prohibited, and the process of setting the required driving force based on the fuel efficiency priority torque (composite torque) is executed.

[0050] The control device for the hybrid vehicle Ve in the embodiment of the present invention may be configured to set an intermediate operating line in addition to the above-mentioned full throttle operating line and fuel efficiency priority operating line, and execute engine control, as shown in Fig. 6. The intermediate operating line is an operating line that connects operating points where the exhaust state of the engine 1 is improved and the fuel efficiency of the engine 1 is improved compared to the above-mentioned full throttle operating line, and where the engine torque is increased compared to the above-mentioned fuel efficiency priority operating line. In other words, the intermediate operating line is an operating line that connects operating points where the exhaust state of the engine 1, such as the displacement and exhaust components, is improved at least compared to the full throttle operating line, and is included in the non-full throttle operating line in the embodiment of the present invention.

[0051] In the control device for the hybrid vehicle Ve according to the embodiment of the present invention, for example, in step S2 in the flowchart of Fig. 3 or Fig. 5, the use of the full-throttle operating line is prohibited, and the required driving force is set based on an intermediate torque (composite torque). The intermediate torque is a composite torque obtained by adding together the engine torque determined based on the intermediate operating line and the motor torque that can be output according to the discharge allowable power of the battery 5.

[0052] In the control device for the hybrid vehicle Ve in the embodiment of the present invention, as shown in Fig. 6, three operating lines, a full throttle operating line, a fuel efficiency priority operating line, and an intermediate operating line, may be set, and engine control may be executed by appropriately selecting three torques (maximum torque, fuel efficiency priority torque, and intermediate torque) determined based on the three operating lines. Alternatively, an intermediate operating line may be set in place of the full throttle operating line and the fuel efficiency priority operating line shown in Fig. 1, and engine control may be executed by appropriately selecting torques (maximum torque and intermediate torque) determined based on the two operating lines, the full throttle operating line and the intermediate operating line.

[0053] As described above, in the control device for a hybrid vehicle according to the embodiment of the present invention, when the first control mode or the CD mode is selected, the operation of the engine 1 based on the full throttle operating line is prohibited. At the same time, the required driving force (i.e., the target driving force in the driving force control) corresponding to a large driving request that maximizes the accelerator opening is set based on a composite torque (i.e., a fuel efficiency priority torque or an intermediate torque) that combines the engine torque when the engine 1 is operated on a non-full throttle operating line such as a fuel efficiency priority operating line or an intermediate operating line, and the motor torque that can be output according to the battery state at that time. Therefore, even when a large driving force that maximizes the accelerator opening is required, the use of the full throttle operating line is avoided, and the deterioration of the exhaust state of the engine 1 is suppressed. In addition, since the maximum torque of the motor that can be output at that time is added to the engine torque based on the non-full throttle operating line, it is possible to appropriately respond to a large driving request. That is, the power performance of the vehicle Ve can be ensured.

[0054] Therefore, according to the control device for the hybrid vehicle Ve in this embodiment of the present invention, it is possible to improve the fuel efficiency of the engine 1 without causing a decrease in the power performance of the vehicle Ve, and also to prevent a deterioration in the exhaust emissions of the engine 1. [Explanation of symbols]

[0055] 1 Engine (ENG) 2. First motor (MG) (motor for generating electricity) 3. Second motor (MG) (drive motor) 4 Power split mechanism (GEAR) 5 Battery (BAT) 6a (Detection section) Engine speed sensor 6b (Detection section) Motor speed sensor 6c (detection section) motor speed sensor 6d (Detection section) SOC sensor 6e (Detection section) Battery current sensor 6f (Detection section) Battery temperature sensor 7 Controller (ECU) 8 Differential Gear 9 Drive shaft 10 Drive wheels 11 Inverter (INV) 12 External power supply Ve vehicle (hybrid vehicle)

Claims

1. A control device for a hybrid vehicle equipped with an engine and a motor as a driving force source, and including a battery for exchanging electric power with the motor, capable of selectively setting at least a first control mode in which the motor is driven by supplying electric power from the battery, and a second control mode in which electric power is not supplied from the battery to the motor, and controlling driving force based on a required driving force that is set corresponding to a vehicle speed and an accelerator opening, A controller for controlling the hybrid vehicle, The controller: Controlling the engine based on at least a full throttle operating line connecting operating points at which the engine outputs a maximum torque when the accelerator opening is at a maximum, and a non-full throttle operating line connecting operating points at which an exhaust gas condition of the engine is improved compared to the full throttle operating line; selecting either the first control mode or the second control mode to run the hybrid vehicle; When the first control mode is selected, the use of the full throttle operation line is prohibited, and the required driving force corresponding to the state where the accelerator opening degree is maximum is set based on a composite torque obtained by combining an output torque of the engine determined based on the non-full throttle operation line and an output torque of the motor that can be output according to the discharge allowable power of the battery, and the driving force is controlled. A control device for a hybrid vehicle.

2. The control device for a hybrid vehicle according to claim 1, The controller: determining a predetermined condition that may cause the exhaust state to deteriorate when the first control mode is selected; When it is determined that there is a possibility that the exhaust gas condition will deteriorate, the use of the full-throttle operation line is prohibited, and the required driving force corresponding to the maximum accelerator opening is set based on the composite torque, and the driving force is controlled. A control device for a hybrid vehicle.

3. The control device for a hybrid vehicle according to claim 1 or 2, the non-full throttle operating line includes a fuel efficiency prioritized operating line that connects operating points at which the exhaust state is improved and the fuel efficiency of the engine is improved as compared to the full throttle operating line, The composite torque includes a fuel efficiency prioritized torque obtained by adding together an output torque of the engine determined based on the fuel efficiency prioritized operation line and an output torque of the motor that can be output according to the discharge allowable power of the battery. A control device for a hybrid vehicle.

4. The control device for a hybrid vehicle according to claim 3, the non-full throttle operating line includes an intermediate operating line connecting operating points at which the exhaust state is improved and the fuel economy is improved as compared with the full throttle operating line, and at which the output torque of the engine is increased as compared with the fuel economy prioritized operating line, the composite torque includes an intermediate torque obtained by adding together an output torque of the engine determined based on the intermediate operating line and an output torque of the motor that can be output according to a discharge allowable power of the battery, The controller: When the first control mode is selected, or when it is determined that the exhaust gas condition is likely to deteriorate, the use of the full-throttle operation line is prohibited, and the required driving force corresponding to the maximum accelerator opening is set based on the intermediate torque, and the driving force is controlled. A control device for a hybrid vehicle.

5. The control device for a hybrid vehicle according to claim 1, the first control mode includes a CD mode in which the motor consumes the stored power of the battery; the second control mode includes a CS mode in which a charge amount of the battery is maintained at a predetermined level; The controller: When the CD mode is selected, the use of the full throttle operation line is prohibited, and the required driving force corresponding to the maximum accelerator opening is set based on the composite torque, and the driving force is controlled. A control device for a hybrid vehicle.

6. The control device for a hybrid vehicle according to claim 5, The controller: determining a predetermined condition that may cause the exhaust state to deteriorate when the CD mode is selected; When it is determined that there is a possibility that the exhaust gas condition will deteriorate, the use of the full-throttle operation line is prohibited, and the required driving force corresponding to the maximum accelerator opening is set based on the composite torque, and the driving force is controlled. A control device for a hybrid vehicle.

7. The control device for a hybrid vehicle according to claim 5 or 6, the non-full throttle operating line includes a fuel efficiency prioritized operating line that connects operating points at which the exhaust state is improved and the fuel efficiency of the engine is improved as compared to the full throttle operating line, The composite torque includes a fuel efficiency prioritized torque obtained by adding together an output torque of the engine determined based on the fuel efficiency prioritized operation line and an output torque of the motor that can be output according to the discharge allowable power of the battery. A control device for a hybrid vehicle.

8. The control device for a hybrid vehicle according to claim 7, the non-full throttle operating line includes an intermediate operating line connecting operating points at which the exhaust state is improved and the fuel economy is improved as compared with the full throttle operating line, and at which the output torque of the engine is increased as compared with the fuel economy prioritized operating line, the composite torque includes an intermediate torque obtained by adding together an output torque of the engine determined based on the intermediate operating line and an output torque of the motor that can be output according to a discharge allowable power of the battery, The controller: When the CD mode is selected or when it is determined that the exhaust gas condition is likely to deteriorate, the use of the full throttle operation line is prohibited, and the required driving force corresponding to the maximum accelerator opening is set based on the intermediate torque, and the driving force is controlled. A control device for a hybrid vehicle.

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