Control device and control method for a hybrid vehicle

Abstract

The present application provides a control device for a hybrid vehicle, which is capable of coordinating a first control rule of controlling a transmission ratio so that an output from an internal combustion engine via a transmission satisfies a required driving force, and a second control rule of controlling a transmission ratio so that a total of a driving force of an electric motor and a driving force of the internal combustion engine is the required driving force. The present application is a device (30) for controlling a hybrid vehicle, the aforementioned hybrid vehicle being provided with an internal combustion engine (11) and an electric motor (13) as a power source capable of generating a driving force of a wheel (18), a transmission (12) being provided between the aforementioned internal combustion engine (11) and the aforementioned wheel (18), a transmission ratio being controlled according to a first control rule, a target transmission ratio being calculated according to a second control rule so that a total of a driving force (Fm) of the electric motor (13) and a driving force (Fe) of the internal combustion engine (11) is a required driving force (Fd), and a parameter (vAp) used in the first control rule being determined based on the target transmission ratio.

Description

Technical Field

[0001] This invention relates to a control device for hybrid vehicles. Background Technology

[0002] Previously, hybrid vehicles were known to possess an internal combustion engine and an electric motor as power sources capable of generating driving force for the wheels, with a transmission installed between the internal combustion engine and the wheels (e.g., Patent Document 1). In such vehicles with a transmission between the internal combustion engine and the wheels, even when the driver is given the required driving force and speed for the wheels, the transmission ratio will vary within a predetermined range, thus allowing for a certain degree of variability in the operating state of the internal combustion engine. Therefore, by controlling the transmission ratio, the operating state of the internal combustion engine can be adjusted to suit a specific purpose.

[0003] Patent document 1: Japanese Patent Application Publication No. 2000-166019.

[0004] Here, the control rule that controls the gear ratio to make the internal combustion engine operate in a state suitable for a certain purpose and that the output from the internal combustion engine via the gearbox satisfies the required driving force is called the first control rule. Furthermore, the control rule that controls the gear ratio to make the internal combustion engine operate in a state suitable for a certain purpose and that the sum of the driving force of the electric motor and the driving force of the internal combustion engine is the required driving force is called the second control rule. Additionally, if the electric motor can generate electricity, the aforementioned driving force of the electric motor also includes the negative value during power generation. The operating state of the internal combustion engine corresponding to the gear ratio achieved according to the first control rule is defined as the first state, and the operating state of the internal combustion engine corresponding to the gear ratio achieved according to the second control rule is defined as the second state.

[0005] In the second control rule, not only the internal combustion engine but also the electric motor provides the required driving force. Therefore, the second state differs from the first state. For example, the second state cannot be achieved by controlling the gear ratio solely according to the first control rule. That is, in hybrid vehicles, the first and second control rules need to be coordinated. Summary of the Invention

[0006] The present invention was made in view of the above-mentioned problems, and provides a control device for a hybrid vehicle that enables coordination between the first control rule and the second control rule.

[0007] According to a certain aspect of the present invention, a control device for a hybrid vehicle is provided for controlling the hybrid vehicle, wherein the hybrid vehicle has an internal combustion engine and an electric motor as power sources capable of generating driving force for the wheels, and a transmission is provided between the internal combustion engine and the wheels, wherein the transmission ratio is controlled according to a first control rule. The device is characterized in that it is configured to calculate a target transmission ratio according to a second control rule, such that the sum of the driving force of the electric motor and the driving force of the internal combustion engine is the required driving force, and the parameters used in the first control rule are determined based on the target transmission ratio.

[0008] As explained above, the first control rule and the second control rule can be coordinated according to the present invention. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating a structural example of a hybrid vehicle according to an embodiment of the present invention.

[0010] Figure 2 This is an example of a transmission line diagram used by the transmission control unit in this embodiment.

[0011] Figure 3 This is an example illustrating the characteristics of the internal combustion engine in this embodiment.

[0012] Figure 4 This is a flowchart illustrating the control processing performed by the hybrid power control unit in this embodiment.

[0013] Figure 5 This is a flowchart illustrating the process of calculating the hypothetical accelerator opening performed by the hybrid power control unit in this embodiment. Detailed Implementation

[0014] Hereinafter, suitable embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, structural elements having substantially the same functional structure are labeled with the same reference numerals, and repeated descriptions are omitted.

[0015] <1. Example of the structure of a hybrid vehicle>

[0016] First, refer to Figure 1 A structural example of a hybrid vehicle using the control device of this embodiment will be described. The drive system of the hybrid vehicle includes an engine 11, an automatic transmission 12, a motor 13, a transfer case 14, and a differential mechanism 15. The power system of the hybrid vehicle includes a battery 20 as a secondary battery.

[0017] Engine 11 is an internal combustion engine that uses gasoline or light oil as fuel. The power generated by engine 11 is transmitted to wheels 18, thereby generating driving force for wheels 18. Wheels 18, for example, are front wheels and function as drive wheels.

[0018] Automatic transmission 12 is positioned in the power transmission path between engine 11 and wheels 18, transmitting the output rotation of engine 11 to the axle 17 side by changing the speed. Engine 11 and automatic transmission 12 function as a vehicle drive unit 10. Automatic transmission 12 is a continuously variable transmission, for example, having a continuously variable transmission (CVT) mechanism and a forward / reverse switching mechanism.

[0019] The CVT is a belt-driven system, consisting of a main pulley connected to the CVT's input shaft (the output shaft of engine 11), a secondary pulley connected to the CVT's output shaft, and a belt wound around the two pulleys. The belt functions as a power transmission component that transmits torque between the two pulleys.

[0020] For example, due to hydraulic pressure, the groove width of each of the two pulleys changes, thereby changing the winding diameter, making it possible to continuously variable transmission of rotation from the input shaft to the output shaft of the CVT. The output shaft of the CVT is connected to the wheel 18 via a reduction gear, a differential mechanism 15, and an axle 17.

[0021] A forward / reverse switching mechanism is located in the power transmission path between the engine 11 and the CVT, and includes, for example, planetary gears, a forward clutch, and a reverse brake. By controlling the forward clutch and the reverse brake, the rotation direction of the CVT's input shaft can be switched, i.e., the vehicle can move forward or backward. By disengaging both the forward clutch and the reverse brake, the torque transmission between the engine 11 and the CVT is cut off.

[0022] Motor 13 is, for example, a three-phase AC rotary motor, connected to battery 20 via an inverter. The output shaft 16 of motor 13 is connected to wheel 18 via reduction gear, differential mechanism 15 and axle 17.

[0023] When the vehicle is in motion, motor 13 uses the electricity from battery 20 to generate power, functioning as an electric motor (drive motor) to generate driving force for driving wheels 18. When the vehicle is regenerating, motor 13 is driven by the power transmitted from the wheel 18 side as the vehicle decelerates, functioning as a generator (generator) to generate electricity.

[0024] The transfer case 14 is located between the output shaft of the automatic transmission 12 (the output shaft of the CVT) and the output shaft 16 of the motor 13, and includes a transfer case gear and a transfer clutch. The transfer case gear may also be integrated with the gear of the differential mechanism 15.

[0025] The transfer clutch, for example, is a friction component that is hydraulically engaged or disengaged, and can be located between the output shaft 16 of the motor 13 and the differential mechanism 15. The transfer case 14 can switch the transmission of torque between the motor 13 and the axle 17 by changing the engagement state of the transfer clutch.

[0026] With the transfer case engaged, in addition to the power output from the engine 11, the power output from the motor 13 is also transmitted to the wheels 18, creating a hybrid driving mode that allows the vehicle to be driven by both the engine 11 and the motor 13. In hybrid driving mode, the motor 13 can also generate electricity using the power transmitted from the engine 11. For example, if there is surplus power from the engine 11, the motor 13 can function as a generator using a portion of the engine 11's power, thereby improving the energy efficiency of the engine 11.

[0027] With the transfer clutch disengaged, only the power output from the engine 11 is transmitted to the wheels 18, forming an engine-driven mode that enables the vehicle to be driven by the engine 11.

[0028] Alternatively, the transfer clutch can also be located between the output shaft of the automatic transmission 12 (the output shaft of the CVT) and the differential mechanism 15.

[0029] <2. Example of the structure of a control device>

[0030] like Figure 1 As shown, the control system of the hybrid vehicle in this embodiment includes an engine control unit (ECU) 31, a transmission control unit (TCU) 32, a motor control unit (MCU) 33, and a hybrid power control unit (HCU) 30.

[0031] Each control unit 30-33 may be partially or entirely composed of, for example, a microcomputer or microprocessor unit. Alternatively, the microcomputer or the like may consist of a central processing unit (CPU) performing various arithmetic operations, a read-only memory (ROM) storing various control programs, random access memory (RAM) used as a working area for data storage and program execution, and an input / output interface (I / O), all interconnected via a bidirectional common bus. Furthermore, each control unit may be partially or entirely composed of updatable firmware or program modules executed according to instructions from the CPU or the like.

[0032] ECU41 and HCU42 are interconnected, enabling bidirectional communication via communication lines such as CAN (Controller Area Network), allowing them to communicate with each other about various information related to control information and controlled objects.

[0033] The ECU 31 is connected to the engine 11 via a communication line, which includes various actuators and sensors, as well as an accelerator pedal opening sensor 41 and a vehicle speed sensor 42. The accelerator pedal opening sensor 41 detects the accelerator opening Ap, which is the amount of accelerator pedal operation. The vehicle speed sensor 42 detects, for example, the rotational speed of the axle 17 or the wheel 18. The ECU 31 detects the vehicle speed (hereinafter referred to as vehicle speed V) based on the signal from the vehicle speed sensor 42.

[0034] Furthermore, the ECU31 is connected to the TCU32 and HCU30, enabling bidirectional communication via communication lines such as CAN (Controller Area Network), allowing for the exchange of various information related to control information and controlled objects. Based on signals input from the aforementioned sensors, TCU32, and HCU30, the ECU31 adjusts the throttle valve opening, ignition timing, and fuel injection quantity, thereby controlling the operating state of the engine 11.

[0035] The TCU32 is connected to the automatic transmission 12 via a communication line. Furthermore, the TCU32 is connected to the HCU30, enabling bidirectional communication via a CAN or other communication line.

[0036] Based on signals from sensors that detect the status of the automatic transmission 12 and the transfer case 14, as well as signals input from the ECU 31 and HCU 30, the TCU 32 controls the oil pump, the various control valves and clutches of the automatic transmission 12, and the clutch of the transfer case 14, thereby controlling the operating status of the automatic transmission 12 and the transfer case 14.

[0037] For example, the TCU32 controls the engagement and disengagement of the transfer clutch, i.e., the switching of travel modes, by controlling the hydraulic pressure.

[0038] Furthermore, the TCU32 functions as a transmission control device that controls the gear ratio of the automatic transmission 12 by controlling the hydraulic pressure. The TCU32 is referenced to, for example... Figure 2 The target pulley ratio of the CVT is determined by using the given speed change curve (Figure shown). Figure 2 In this context, vehicle speed V corresponds to the rotational speed of the CVT's output shaft, and engine speed Ne corresponds to the rotational speed of the CVT's input shaft. Therefore, the ratio of engine speed Ne to vehicle speed V is equivalent to the pulley ratio R.

[0039] Pulley ratio R in Figure 2 The speed can vary between the lowest line 101 and the highest line 102, represented by dashed lines. Multiple speed change lines 103 are defined so that the larger the accelerator opening Ap becomes, the greater the engine speed Ne becomes; in other words, the pulley ratio R is on the lower side.

[0040] Figure 3Here's an example illustrating the characteristics of engine 11. The maximum torque 201 of engine 11 is represented by a thick solid line, the constant output line 202 by a thin dashed line, and the constant fuel consumption line 203 by a thin solid line. The point where the constant fuel consumption line 203 intersects with the constant output line 202 represents the optimal fuel consumption operating state of engine 11. The dotted line connecting these points is the optimal fuel consumption line 204. If engine 11 operates on this optimal fuel consumption line 204, its fuel consumption can be minimized. Figure 2 In the gear shift diagram, multiple gear shift lines 103 are specified so that the engine 11 operates at the optimal fuel consumption line 204.

[0041] The MCU33 includes an inverter and a motor controller. The inverter converts the DC power supplied from battery 20 into AC power to supply the motor 13, driving the motor 13. The inverter also converts the AC power supplied from motor 13 into DC power to supply the battery 20, charging the battery 20.

[0042] The motor controller is connected to the inverter and motor 13 via a communication line. Furthermore, the motor controller is connected to the HCU30, enabling bidirectional communication via a CAN or other communication line. Based on signals input from various sensors on the motor 13 and the HCU30, the motor controller outputs command signals to the inverter to control the operating state of the motor 13.

[0043] The HCU30 comprehensively controls the drive system and power system, enabling the vehicle to achieve the required driving force and operate in the optimal state from the perspective of overall vehicle energy efficiency, thus functioning as a control device for hybrid vehicles.

[0044] HCU30 is connected to other control units 31, 32, and 33, and is also connected to battery 20 via a communication line. Battery 20 inputs information such as State of Charge (SOC), temperature, voltage, and current to HCU30. To improve energy efficiency and suppress overcharging and over-discharging of battery 20, HCU30 outputs command signals to MCU33 to control the operating state of motor 13, thereby controlling the SOC to vary within a predetermined range.

[0045] In addition to the information from the battery 20, the HCU30 also processes other information such as the vehicle speed V and accelerator opening Ap input from the ECU31 and information from the TCU32, and outputs signals to the ECU31 and TCU32, thereby controlling the operating state of the engine 11 and the working state of the automatic transmission 12.

[0046] (flow chart)

[0047] Figure 4This describes the process flow executed by the HCU30 in this embodiment. This process is repeated at a predetermined cycle, at least in hybrid driving mode.

[0048] In step S1, HCU30 reads various information. Specifically, it reads information about the engine 11, vehicle speed V, and accelerator opening Ap from ECU31. It reads information about the CVT from TCU32. It reads temperature, current, voltage, and speed from MCU33 as information about the motor 13. It reads SOC, temperature, and voltage from battery 20 as information about battery 20.

[0049] In step S2, HCU30 calculates the required driving force Fd based on the vehicle speed V and the accelerator opening Ap, for example, by referring to a predetermined diagram.

[0050] In step S3, HCU30 samples the possible states that multiple engines 11 can obtain, i.e., the possible states of the engines, under the current operating state of the vehicle. Each possible engine state is assigned an exponent i. i is, for example, a natural number from 1 to n1.

[0051] For example, based on CVT information, HCU30 calculates the possible shift range of the CVT, in other words, the variable range of the pulley ratio R. If this range is divided into n1 equal parts, the achievable pulley ratio R(i) for any i can be specified. The engine speed Ne(i) can be specified based on this pulley ratio R(i) and the vehicle speed V. The engine speed Ne(i) corresponds to the possible engine state i.

[0052] In step S4, HCU30 samples the possible states that motor 13 can obtain under the current operating conditions of multiple vehicles. An exponent j is assigned to each possible motor state. j is, for example, a natural number from 1 to n².

[0053] For example, HCU30 calculates the possible range of the driving force Fm of the vehicle generated by motor 13 based on information from battery 20 and motor 13; in other words, it calculates the range of the driving force Fm generated by the power output by motor 13. If this range is divided into n² equal parts, the driving force Fm(j) that can be achieved by motor 13 for any given j can be determined. The motor torque Tm(j) can be calculated based on the tire diameter of wheel 18, the gear ratio between motor 13 and axle 17, and the driving force Fm(j). Torque Tm(j) corresponds to the possible state j of the motor.

[0054] Here, the driving force Fm and torque Tm can be taken as positive values ​​when the battery 20 is discharging, i.e. when the motor 13 is moving, or as negative values ​​when the battery 20 is charging, i.e. when the motor 13 is regenerating.

[0055] In step S5, HCU30 calculates the engine torque Te(i,j) under possible engine state i and possible motor state j.

[0056] For example, HCU30 calculates the driving force Fe(j) generated by engine 11 in possible motor state j by subtracting the driving force Fm(j) calculated in step S4 from the required driving force Fd calculated in step S2. Based on the engine speed Ne(i) and vehicle speed V calculated in step S3, the gear ratio between engine 11 and axle 17 in possible engine state i is calculated. This gear ratio includes the CVT pulley ratio R. The engine torque Te(i,j) can be calculated based on this gear ratio, the tire diameter of wheel 18, and the driving force Fe(j).

[0057] Here, it is also possible that the engine 11, based on the information of the engine 11, can specifically output a maximum torque and a minimum torque, and impose a limit so that the calculated engine torque Te(i,j) does not exceed the maximum torque or the minimum torque.

[0058] In step S6, HCU30 calculates the energy consumption Qe(i,j) of engine 11 under possible engine state i and possible motor state j.

[0059] For example, HCU30 calculates the hourly fuel consumption of engine 11 under possible engine state i and possible motor state j based on engine speed Ne(i) and engine torque Te(i,j) and information about engine 11. If this is converted into energy [kW], the consumed energy Qe(i,j) can be calculated.

[0060] In step S7, HCU30 calculates the energy consumption Qm(j) of motor 13 under possible motor state j.

[0061] For example, HCU30 calculates the output of motor 13 in possible state j by referring to a predetermined motor efficiency diagram based on the specifications of motor 13, based on the motor torque Tm(j) and motor speed Nm. Furthermore, referring to the motor efficiency diagram, a coefficient F is calculated based on the SOC of battery 20. Coefficient F is used to convert the output of motor 13, as electrical energy, into the energy consumed by fuel, i.e., heat generation. By multiplying the output of motor 13 in possible state j by the coefficient F, the consumed energy Qm(j) can be calculated.

[0062] In step S8, HCU30 designates the combination that minimizes the total energy consumption Qe(i,j) and energy consumption Qm(j) in the combination (i,j) of possible engine state i and possible motor state j as the optimal state (I,J).

[0063] In step S9, HCU30 outputs command signals for achieving the optimal state (I, J) to ECU31, TCU32, and MCU33. Specifically, a command signal setting the torque Te(I, J) of engine 11 in state (I, J) to the target engine torque is transmitted to ECU31. A command signal setting the torque Tm(J) of motor 13 in state J to the target motor torque is transmitted to MCU33. Furthermore, the hypothetical accelerator opening vAp is calculated and transmitted to TCU32.

[0064] Alternatively, HCU30 can replace torque Te(I,J) and transmit the accelerator opening Ap, which is equivalent to torque Te(I,J), as a command signal to ECU31.

[0065] Furthermore, the order of the above steps can be changed appropriately. For example, steps S2 to S4 can be interchanged appropriately.

[0066] Figure 5 This describes the process of HCU30 calculating the hypothetical accelerator opening vAp in step S9.

[0067] In step S91, HCU30 calculates the driving force Fm(J) of motor 13 under optimal motor state J based on the tire diameter of wheel 18, the gear ratio between motor 13 and axle 17 and motor torque Tm(J).

[0068] In step S92, HCU30 subtracts the driving force Fm(J) calculated in step S91 from the required driving force Fd, thereby calculating the vehicle driving force Fe(J) of engine 11 under the optimal motor state J. The driving force Fe(J) is converted into torque based on the tire diameter of wheel 18 and divided by the target engine torque Te(I,J), and the target pulley ratio R(I,J) of CVT is calculated based on the result.

[0069] Furthermore, the method for calculating the target pulley ratio R(I,J) is not limited to this. For example, it is also possible to calculate the output shaft speed of the CVT based on the gear ratio between the CVT and the wheel 18 and the vehicle speed V, divide the engine speed Ne(I) of the engine 11 under the optimal state I by the output shaft speed mentioned above, and calculate the target pulley ratio R(I,J) based on the result.

[0070] In step S93, HCU30, based on the target pulley ratio R(I,J) and vehicle speed V, refers to the same reference used by TCU32. Figure 2 From the graph, calculate the hypothetical accelerator opening vAp.

[0071] <3. Examples of Control Device Operation>

[0072] As mentioned above, the TCU32 uses, for example, Figure 2The diagram shown controls the gear ratio of the automatic transmission 12, specifically the pulley ratio R of the CVT, so that the engine 11 operates at the optimal fuel consumption line 204. Alternatively, the TCU 32 can replace the diagram with a calculation formula. This gear ratio control rule will be referred to as the first control rule.

[0073] The first control rule uses, for example, the accelerator opening Ap and the vehicle speed V as parameters to control the gear ratio. The automatic transmission 12 is a continuously variable transmission (CVT), so the controlled gear ratio can change steplessly.

[0074] HCU30, for example, executes Figure 4 and Figure 5 The processing described above calculates the target pulley ratio R(I, J), which is the target gear ratio, such that the sum of the driving force Fm of motor 13 and the driving force Fe of engine 11 is the required driving force Fd, and the sum of the energy consumed Qe of engine 11 and the energy consumed Qm of motor 13 is minimized. Hereinafter, the gear ratio control rule that includes such a target gear ratio calculation rule will be referred to as the second control rule.

[0075] The second control rule is to calculate the torque Te(i,j) and speed Ne(i) corresponding to the multiple gear ratios currently achievable by the automatic transmission 12, representing the multiple operating states currently achievable by the engine 11. Figure 4 Steps S3-S5). From these multiple operating states (torque Te(i,j), speed Ne(i)), select the one with the smallest total energy consumption Qe, Qm as the operating state's torque Te(i,j) and speed Ne(i) (steps S6-S8). Thus, based on the selected operating state (torque Te(i,j) or speed Ne(i)), calculate the target pulley ratio R(i,j) as the target gear ratio (step S9). Figure 5 Steps S91 and S92).

[0076] HCU30, for example, uses Figure 2 The diagram shown determines the hypothetical accelerator opening vAp based on the target pulley ratio R(I,J) and vehicle speed V. Figure 5 Step S93). This is equivalent to performing the inverse operation of the accelerator opening Ap using the first control rule. Alternatively, the HCU30 can use a calculation formula instead of a graph. The HCU30 outputs the determined hypothetical accelerator opening vAp to the TCU32 ( Figure 4 Step S9).

[0077] The TCU32 uses the hypothetical accelerator opening vAp received from the HCU30 to control the gear ratio according to the first control rule. The TCU32, for example, uses... Figure 2The diagram shown illustrates how the gear ratio is set and the CVT controlled based on the vehicle speed V received from the hypothetical accelerator opening vAp and ECU31. Alternatively, TCU32 can be used instead of the diagram, employing calculation formulas, etc.

[0078] In addition, the accelerator opening Ap or vehicle speed V used in the first or second control rule mentioned above can be estimated values ​​obtained from calculations or command values, in addition to the sensor detection values.

[0079] <4. Significance of the technical concepts grasped from this implementation method>

[0080] Generally, in vehicles with a transmission between the engine and wheels, the transmission ratio will vary within a predetermined range even when the required driving force and speed are applied to the wheels. Therefore, the operating state of the internal combustion engine has a certain degree of variability. Thus, by controlling the transmission ratio, the engine's operating state can be made suitable for a certain purpose.

[0081] The first control rule of this embodiment is to control the gear ratio so that, assuming only the engine 11 as the driving force source, the output of the unit 10 consisting of the engine 11 and the automatic transmission 12 meets the required driving force Fd. Hereinafter, the operating state of the engine 11 corresponding to this gear ratio will be referred to as the first state.

[0082] The second control rule is to set a target gear ratio for the automatic transmission 12 so that the combined output of the unit 10 and the motor 13 meets the required driving force Fd. Hereinafter, the operating state of the engine 11 corresponding to this target gear ratio will be referred to as the second state.

[0083] In the second control rule, the driving force Fd is required to be provided not only by the output of unit 10 but also by the output of motor 13. Therefore, the second state differs from the first state, and the two states will diverge. For example, in the case where the total energy consumption Qe and Qm is minimized by using engine 11 to drive motor 13 to generate electricity, Figure 3 In the second state, the torque Te(I, J) will be the value at point 206, but this is different from the value at point 205 in the first state. That is, the second state cannot be achieved if the gear ratio is controlled only according to the first control rule. Therefore, in hybrid vehicles, the first control rule and the second control rule need to be coordinated.

[0084] In contrast, the HCU30 of this embodiment determines the parameter used under the first control rule, namely the accelerator opening Ap (hypothetical accelerator opening vAp), based on the target gear ratio calculated according to the second control rule, namely the target pulley ratio R(I, J). Therefore, the target gear ratio calculated according to the second control rule is added to the first control rule, so the target gear ratio can be achieved even according to the first control rule, thus achieving the second state. That is, in the hybrid vehicle, the first and second control rules are coordinated to meet the required driving force Fd, and the purpose of the second control rule can be achieved.

[0085] In other words, the target pulley ratio R(I, J), which is the target gear ratio, is calculated based on the driving force Fe allocated to unit 10 in the required driving force Fd. Therefore, the parameters (hypothetical accelerator opening vAp) determined based on the above-mentioned target gear ratio include information from the output of unit 10. By controlling the gear ratio with such information using the first control rule, the aforementioned deviation between the first state and the second state can be eliminated.

[0086] Furthermore, the structure of the drive system of a hybrid vehicle is not limited to the structure of the drive system in this embodiment. For example, a motor may be provided between the engine and the transmission. In short, if a hybrid vehicle is provided with a transmission between the engine and the wheels, and the driving force of the wheels can be generated by either the engine or the motor, then the control described in this embodiment can be applied.

[0087] In the drive system of this embodiment, the power of the motor 13 is transmitted to the opposite side of the automatic transmission 11, namely the axle 17, rather than to the engine 11. Therefore, the first control rule for the gear ratio executed by the TCU 32 may not consider the power of the motor 13 or may require the drive force Fd to be provided solely by the output of the unit 10. In this case, the aforementioned effects of the control of the HCU 30 are effectively achieved.

[0088] Alternatively, the second control rule can also be a control rule used to make the operating state of the engine 11 suitable for improving exhaust performance, etc. For example, the target pulley ratio R(I, J), which is the target gear ratio, can be calculated to minimize the exhaust volume of the engine 11.

[0089] The second control rule in the implementation is a control rule for adjusting the operating state of the engine 11 to a state that improves the energy efficiency of both the engine 11 and the motor 13. For example, the HCU30 calculates the target pulley ratio R(I,J) to minimize the total energy consumption Qe and Qm, thus achieving a second state where the energy efficiency of the engine 11 and motor 13 is higher compared to other states. By incorporating this viewpoint of the second control rule into the first control rule to reflect it, the overall energy efficiency of the hybrid vehicle can be improved.

[0090] Alternatively, the first control rule can also be a control rule used to make the engine 11 operate in a state that is suitable for improving the vehicle's driving performance (acceleration performance, etc.).

[0091] The first control rule in this embodiment is a control rule for adjusting the operating state of the engine 11 to a state that improves energy efficiency. Therefore, even when traveling solely by the driving force of the engine 11, the energy efficiency of the hybrid vehicle can be improved.

[0092] The second control rule is as follows: corresponding to the multiple gear ratios currently achievable by the automatic transmission 12, the torque Te(i,j) and speed Ne(i) of the engine 11 as multiple operating states currently achievable are calculated. Based on the selected torque Te(i,j) or speed Ne(i) as an operating state, the target pulley ratio R(i,j) is calculated as the target gear ratio. In this way, the second control rule calculates the target gear ratio based on the multiple gear ratios currently achievable by the automatic transmission 12, thereby achieving the gear ratio controlled based on this target gear ratio more reliably than the second state.

[0093] The first control rule controls the gear ratio based on the accelerator opening Ap and the vehicle speed V. The accelerator opening Ap and the vehicle speed V correspond to the required driving force Fd, and the vehicle speed V corresponds to the speed of wheel 18. Therefore, when the required driving force Fd of wheel 18 or the speed of wheel 18 changes, the gear ratio controlled according to the first control rule will change accordingly. At this time, the second control rule can also achieve the second state by calculating the target gear ratio based on the multiple gear ratios currently available to the automatic transmission 12.

[0094] In addition, the automatic transmission 12 can control the gear ratio with the help of a certain control device, and it can also be a multi-stage or dual-clutch automatic transmission, or an automatic MT that automates a manual transmission.

[0095] The automatic transmission 12 in this embodiment is a continuously variable transmission (CVT). Therefore, when the gear ratio controlled by the first control rule changes steplessly, the second control rule also calculates the target gear ratio based on the multiple gear ratios obtainable by the automatic transmission 12, thereby achieving the second state. Furthermore, by precisely controlling the gear ratio steplessly, the operating state of the engine 11 can be brought closer to its optimal state.

[0096] Alternatively, TCU32 can also be part of HCU30. In other words, the control unit that controls the gear ratio according to the first control rule can also be part of the control device of a hybrid vehicle.

[0097] The hybrid vehicle of this embodiment has a TCU32 that controls the gear ratio according to the first control rule, and the HCU30 outputs the determined parameters to the TCU32. Therefore, the TCU32, which is conventionally used in engine-driven vehicles, can be used for the control of hybrid vehicles as a separate component other than the HCU30.

[0098] The aforementioned parameters can also be vehicle speed V, etc. For example, HCU30 can also determine the hypothetical vehicle speed vV, which is used as a parameter in the first control rule, based on the target pulley ratio R(I,J) and accelerator opening Ap. That is, the parameters received by TCU32 are generally used in typical engine-driven vehicles. In other words, if TCU32 is originally used under the first control rule, it can be used for the control of hybrid vehicles without significantly changing the previous structure or computational content of TCU32.

[0099] The parameter described above in this embodiment is the accelerator opening Ap. For example, the HCU30 determines the hypothetical accelerator opening vAp, which is a parameter used in the first control rule, based on the target pulley ratio R(I, J) as the target gear ratio and the vehicle speed V. Thus, even when using the vehicle speed V and the like as the above parameters, the response is also better, and the TCU32 can control the gear ratio to achieve the second state of the engine 11.

[0100] The above description, with reference to the accompanying drawings, details suitable embodiments of the present invention, but the present invention is not limited to these examples. It is obvious that anyone skilled in the art to which this invention pertains will be able to conceive of various modifications or alterations within the scope of the technical concept described in the claims, and these modifications also fall within the technical scope of the present invention.

[0101] Explanation of reference numerals in the attached figures

[0102] 11. Internal combustion engine, 12. Transmission, 13. Electric motor, 18. Wheels, 30. Control device for hybrid vehicles.

Claims

1. A control device (30) for a hybrid vehicle, used to control the hybrid vehicle, wherein the hybrid vehicle has an internal combustion engine (11) and an electric motor (13) as power sources capable of generating driving force for wheels (18), and a transmission (12) is provided between the internal combustion engine (11) and the wheels (18) to control the gear ratio according to a first control rule, wherein the first control rule controls the gear ratio in such a way that the output from the internal combustion engine via the transmission satisfies the required driving force, using accelerator opening (Ap) and vehicle speed (V) as parameters, characterized in that, The configuration is as follows: the target gear ratio is calculated according to the second control rule, such that the sum of the driving force (Fm) of the aforementioned electric motor (13) and the driving force (Fe) of the aforementioned internal combustion engine (11) is the required driving force (Fd); and the hypothetical accelerator opening (vAp) used in the aforementioned first control rule is determined based on the aforementioned target gear ratio and vehicle speed (V). The aforementioned second control rule is a control rule used to make the operating state of the aforementioned internal combustion engine (11) adapt to the improved energy efficiency of the aforementioned internal combustion engine (11) and the aforementioned electric motor (13).

2. The control device (30) for a hybrid vehicle as described in claim 1, characterized in that, The aforementioned second control rule is to calculate the multiple operating states that the aforementioned internal combustion engine (11) can currently obtain, corresponding to the multiple gear ratios that the aforementioned transmission (12) can currently obtain, and to calculate the aforementioned target gear ratio based on one of the multiple operating states selected from the aforementioned multiple operating states.

3. The control device (30) for a hybrid vehicle as described in claim 1, characterized in that, The aforementioned speed changer (12) is a continuously variable speed (CVT).

4. The control device (30) for a hybrid vehicle as described in claim 2, characterized in that, The aforementioned speed changer (12) is a continuously variable speed (CVT).

5. The control device (30) for a hybrid vehicle as described in any one of claims 1 to 4, characterized in that, The aforementioned hybrid vehicle has a transmission control device (32) that controls the transmission ratio of the aforementioned transmission (12) according to the aforementioned first control rule. The control device (30) of the aforementioned hybrid vehicle will output the aforementioned hypothetical accelerator opening (vAp) to the aforementioned transmission control device (32).

6. A control method for a hybrid vehicle, wherein the hybrid vehicle comprises an internal combustion engine (11) and an electric motor (13) as power sources capable of generating driving force for wheels (18), and a transmission (12) is provided between the internal combustion engine (11) and the wheels (18) to control the gear ratio according to a first control rule, wherein the first control rule controls the gear ratio in such a way that the output from the internal combustion engine via the transmission satisfies the required driving force, using accelerator opening (Ap) and vehicle speed (V) as parameters. Its features are, The configuration is as follows: the target gear ratio is calculated according to the second control rule, such that the sum of the driving force (Fm) of the aforementioned electric motor (13) and the driving force (Fe) of the aforementioned internal combustion engine (11) is the required driving force (Fd), and the hypothetical accelerator opening (vAp) used in the aforementioned first control rule is determined based on the aforementioned target gear ratio. The aforementioned second control rule is a control rule used to make the operating state of the aforementioned internal combustion engine (11) adapt to the improved energy efficiency of the aforementioned internal combustion engine (11) and the aforementioned electric motor (13).

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