Hybrid vehicle control device

Abstract

To provide a hybrid vehicle control device capable of improving fuel economy when a transmission shifts gears.SOLUTION: A hybrid vehicle comprises: an engine 2; a first motor generator 4 which generates power with drive force of the engine 2; a transmission 3 which has a plurality of shift gears and outputs the drive force input from the engine 2 by shifting the gears; and a control section 8 which drives the engine 2 by supplying fuel thereto while the transmission 3 is shifting the gears with a drive shaft of the engine 2 connected to an input shaft of the transmission 3 to cancel out engine torque generated from the engine 2 with a power generation load of the first motor generator 4 and thereby zeroing torque transferred from the input shaft of the transmission 3 to an output shaft of the transmission 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] DE 10 2004 033 333 A1 describes a transmission for a motor vehicle with hybrid propulsion, comprising a heat engine and an electric motor.

[0003] Furthermore, Patent Document 1 describes a structure in which an electric motor is disposed at one end of a primary line, and a heat engine is disposed at a second end of the primary line opposite the first end.

[0004] In this way, the engine drive shaft is constantly connected to the transmission input shaft. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2017-505887 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 does not fully describe engine control during gear shifting of the transmission, and there is room for improvement in improving fuel efficiency during gear shifting of the transmission.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a control device for a hybrid vehicle that can improve fuel efficiency when the transmission is shifted. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention is a control device for a hybrid vehicle that includes an engine, a motor generator that generates electricity using the driving force of the engine, and a transmission that has multiple gear stages and changes and outputs the driving force input from the engine, and includes a control unit that, while the transmission is shifting gears, supplies fuel to the engine to drive the engine while keeping the drive shaft of the engine and the input shaft of the transmission connected, and cancels the engine torque generated by the engine with the generating load of the motor generator, thereby making the torque transmitted from the input shaft of the transmission to the output shaft of the transmission zero. Effect of the Invention

[0009] In this way, according to the present invention, it is possible to improve fuel efficiency when the transmission is shifting gears. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a control device for a hybrid vehicle according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of engine control by the control device for a hybrid vehicle according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A control device for a hybrid vehicle according to one embodiment of the present invention is a control device for a hybrid vehicle that includes an engine, a motor generator that generates electricity using the driving force of the engine, and a transmission that has a plurality of gear stages and changes and outputs the driving force input from the engine, and is configured to include a control unit that, while the transmission is shifting gears, supplies fuel to the engine to drive the engine while keeping the engine drive shaft and the transmission input shaft connected, and cancels the engine torque generated by the engine with the power generation load of the motor generator, thereby reducing the torque transmitted from the transmission input shaft to the transmission output shaft to zero.

[0012] As a result, the control device for a hybrid vehicle according to one embodiment of the present invention can improve fuel efficiency when the transmission is shifted. EXAMPLES

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control device for a hybrid vehicle according to an embodiment of the present invention will now be described in detail with reference to the drawings.

[0014] In FIG. 1, a hybrid vehicle 1 equipped with a hybrid vehicle control device according to one embodiment of the present invention is configured to include an engine 2, a transmission 3, a first motor generator 4 serving as a motor generator, a second motor generator 5, an inverter 6, a battery 7, and a control unit 8.

[0015] A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 is configured to perform a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, for each cylinder.

[0016] The transmission 3 changes the driving force input from the engine 2 at a gear ratio corresponding to one of a plurality of gear stages, and drives left and right drive wheels 11 via a differential 9 and a drive shaft 10. The transmission 3 includes a speed change mechanism (not shown) having a plurality of constantly meshing gear stages made of a parallel shaft gear mechanism, and an actuator (not shown).

[0017] A dry single-plate clutch 31 is provided between the engine 2 and the transmission 3, and the clutch 31 connects or disconnects the power transmission between the engine 2 and the transmission 3. In other words, the clutch 31 functions as a power transmission mechanism that switches the power transmission between the engine 2 and the drive wheels 11 between transmission and non-transmission.

[0018] The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and an actuator (not shown) switches the speed change gears in the speed change mechanism and engages and disengages the clutch 31.

[0019] The first motor generator 4 is constantly connected to the input shaft of the transmission 3. The first motor generator 4 has a function as an electric motor that is driven by power supplied from a battery 7 via an inverter 6, and a function as a generator that generates electricity by the rotational force input to the input shaft of the transmission 3.

[0020] The second motor generator 5 is constantly gear-connected to the input gear of the differential 9. The second motor generator 5 has a function as an electric motor that is driven by power supplied from the battery 7 via the inverter 6, and a function as a generator that generates power by the reverse driving force input from the differential 9.

[0021] Under the control of the control unit 8, the inverter 6 converts the DC power supplied from the battery 7 into three-phase AC power and supplies it to the first motor generator 4 and the second motor generator 5, and also converts the three-phase AC power generated by the first motor generator 4 and the second motor generator 5 into DC power to charge the battery 7. The battery 7 is formed of a secondary battery such as a lithium ion battery.

[0022] In this way, the hybrid vehicle 1 forms a parallel hybrid system in which the power of the engine 2, the first motor generator 4, and the second motor generator 5 can be used to drive the hybrid vehicle 1, and the hybrid vehicle 1 is configured to run using the power output by at least one of the engine 2, the first motor generator 4, and the second motor generator 5.

[0023] The control unit 8 is composed of a computer unit equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0024] The ROM of this computer unit stores a program for causing the computer unit to function as the control unit 8, together with various constants and various maps.

[0025] That is, the CPU executes the programs stored in the ROM using the RAM as a working area, and these computer units function as the control unit 8 in this embodiment.

[0026] To an input port of the control unit 8, various sensors including an engine speed sensor 81 and a rotation sensor 82 are connected.

[0027] The engine speed sensor 81 detects the engine speed, which is the engine speed of the engine 2. The rotation sensor 82 detects the rotation speed of the output shaft of the transmission 3.

[0028] On the other hand, an output port of the control unit 8 is connected to various controlled objects including the inverter 6 and the actuator of the transmission 3, as well as an injector (not shown).

[0029] In this embodiment, while the transmission 3 is shifting, the control unit 8 keeps the drive shaft of the engine 2 connected to the input shaft of the transmission 3, supplies fuel to the engine 2 to drive the engine 2, and cancels the torque generated by the engine 2 with the power generation load of the first motor generator 4, thereby making the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 zero.

[0030] The control unit 8, for example, adjusts the power generation load of the first motor generator 4 so that the engine rotation speed (the rotation speed of the input shaft of the transmission 3) is the same as the rotation speed of the output shaft of the transmission 3, thereby making the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 zero.

[0031] When the control unit 8 determines that the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 has become zero, it disengages the gear of the speed change mechanism of the transmission 3. At this time, it is preferable that the control unit 8 causes the second motor generator 5 to cancel the inertia from the output shaft of the transmission 3 to the drive wheels 11, and substitute for the driving force that the engine 2 had transmitted to the output shaft of the transmission 3 before the gear change.

[0032] When the gear shifting mechanism of the transmission 3 is disengaged, the control unit 8 adjusts the power generation load of the first motor generator 4 so that the engine speed matches the speed of the destination gear shift relative to the speed of the output shaft of the transmission 3. At this time, the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 is maintained at zero by canceling the inertia of the input shaft of the transmission 3 with the first motor generator 4.

[0033] When the engine speed becomes equal to the rotational speed of the output shaft of transmission 3 and the rotational speed of the engine becomes equal to the rotational speed of the destination gear stage, the control unit 8 engages the destination gear, stops canceling the torque of the input shaft of transmission 3, and transmits the engine driving force from the input shaft of transmission 3 to the output shaft of transmission 3 through the gears of the transmission mechanism.

[0034] When the control unit 8 supplies fuel to the engine 2 to drive the engine 2 while keeping the drive shaft of the engine 2 and the input shaft of the transmission 3 connected during gear shifting of the transmission 3, it is preferable that the control unit 8 drives the engine 2 in a range with high thermal efficiency.

[0035] As shown in FIG. 2, for example, at the start of the shift, the control unit 8 shifts the driving state of the engine 2 to a first engine operating point (operating point indicated by the arrow A in the figure) in a region where the engine speed is the same as before the shift and the engine thermal efficiency is higher than before the shift, and before the shift is completed, the control unit 8 shifts the driving state of the engine 2 to a second engine operating point (operating point indicated by the arrow B in the figure) in a region where the engine speed is the same as the target engine speed after the shift and the engine thermal efficiency is higher.

[0036] The target engine speed after shifting is the engine speed at which the torque transmitted from the input shaft of transmission 3 to the output shaft of transmission 3 becomes zero, calculated from the gear stage to which the gear is shifted and the current rotation speed of the output shaft of transmission 3.

[0037] Thus, in this embodiment, while the transmission 3 is shifting, the control unit 8 keeps the drive shaft of the engine 2 connected to the input shaft of the transmission 3, supplies fuel to the engine 2 to drive the engine 2, and cancels the torque generated by the engine 2 with the power generation load of the first motor generator 4, thereby making the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 zero.

[0038] As a result, while the transmission 3 is shifting, the drive shaft of the engine 2 and the input shaft of the transmission 3 remain connected, fuel is supplied to the engine 2 to drive the engine 2, and the torque generated by the engine 2 is canceled by the power generation load of the first motor generator 4, so that the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 is made zero. This improves fuel efficiency.

[0039] Conventionally, gear changes were performed by disengaging the clutch 31 and waiting for the engine speed to drop due to pumping loss and friction loss, but in this embodiment, a portion of the wasted energy can be recovered.

[0040] During gear shifting of the transmission 3, the drive shaft of the engine 2 and the input shaft of the transmission 3 remain connected, fuel is supplied to the engine 2 to drive the engine 2, and the torque generated by the engine 2 is canceled by the power generation load of the first motor generator 4, so that the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 is made zero. This increases the opportunities for fuel-based power generation.

[0041] During gear shifting of the transmission 3, the drive shaft of the engine 2 and the input shaft of the transmission 3 remain connected, fuel is supplied to the engine 2 to drive the engine 2, and the torque generated by the engine 2 is canceled by the power generation load of the first motor generator 4, so that the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 is made zero. This makes it possible to reduce changes in the throttle opening, fuel injection, and ignition timing of the engine 2 before, during, and after the gear shift.

[0042] In addition, when the control unit 8 supplies fuel to the engine 2 to drive the engine 2 while the transmission 3 is shifting, the control unit 8 drives the engine 2 in a range with high thermal efficiency while keeping the drive shaft of the engine 2 and the input shaft of the transmission 3 connected.

[0043] As a result, while the transmission 3 is shifting, the drive shaft of the engine 2 and the input shaft of the transmission 3 remain connected, fuel is supplied to the engine 2, the engine 2 is driven in a region of high thermal efficiency, and the torque generated by the engine 2 is canceled by the power generation load of the first motor generator 4, so that the torque transmitted from the input shaft of the transmission 3 to the output shaft of the transmission 3 is made zero. This improves system efficiency and improves fuel efficiency.

[0044] In addition, when the transmission 3 starts to shift, the control unit 8 shifts the driving state of the engine 2 to a first engine operating point in a region where the engine speed is the same as before the shift starts and the engine thermal efficiency is higher than before the shift, and before the shift is completed, shifts the driving state of the engine 2 to a second engine operating point in a region where the engine speed is the same as the target engine speed after the shift and the engine thermal efficiency is higher.

[0045] As a result, when the transmission 3 starts shifting, the driving state of the engine 2 is shifted to a first engine operating point in a region where the engine speed is the same as before the shifting start and the engine thermal efficiency is higher than before the shifting, and before the shifting is completed, the driving state of the engine 2 is shifted to a second engine operating point in a region where the engine thermal efficiency is higher and the engine speed is the same as the target engine speed after the shifting. This makes it possible to maximize the time during which the engine operates in a region where the engine thermal efficiency is high during the shifting.

[0046] When the transmission 3 starts shifting, the driving state of the engine 2 is shifted to a first engine operating point in a region where the engine speed is the same as before the shifting start and the engine thermal efficiency is higher than before the shifting, and before the shifting is completed, the driving state of the engine 2 is shifted to a second engine operating point in a region where the engine speed is the same as the target engine speed after the shifting and the engine thermal efficiency is higher. This makes it possible to reduce changes in the throttle opening, fuel injection, and ignition timing of the engine 2 before, during, and after the shifting.

[0047] In this embodiment, the rotation speed of the input shaft of the transmission 3 is detected by the engine rotation speed sensor 81, but a sensor for detecting the rotation speed of the input shaft of the transmission 3 may be provided.

[0048] Furthermore, although the rotation speed of the output shaft of the transmission 3 is detected by the rotation sensor 82, the rotation speed of the drive shaft 10 or the drive wheels 11 may be detected and the rotation speed of the output shaft of the transmission 3 may be calculated from the detected rotation speed.

[0049] In this embodiment, an example has been described in which the control unit 8 performs various determinations and calculations based on various sensor information, but this is not limited thereto. The hybrid vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various determinations and calculations may be performed by the external device based on the detection information of the various sensors transmitted from the communication unit. The determination results and calculation results may be received by the communication unit, and various controls may be performed using the received determination results and calculation results.

[0050] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made thereto without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0051] 1 Hybrid vehicles 2 Engine 3. Transmission 4 First motor generator (motor generator) 6 Inverter 8. Control Unit 81 Engine speed sensor 82 Rotation Sensor

Claims

1. A control device for a hybrid vehicle including an engine, a motor generator that generates electricity using a driving force of the engine, and a transmission that has a plurality of speed-change gear stages and changes the speed of the driving force input from the engine and outputs the driving force, A control device for a hybrid vehicle comprising a control unit that, while the transmission is shifting, keeps the drive shaft of the engine and the input shaft of the transmission connected, supplies fuel to the engine to drive the engine, and cancels the engine torque generated by the engine with the power generation load of the motor generator, thereby reducing the torque transmitted from the input shaft of the transmission to the output shaft of the transmission to zero.

2. 2. The control device for a hybrid vehicle according to claim 1, wherein, during gear shifting of the transmission, the control unit keeps the engine drive shaft and the transmission input shaft connected, supplies fuel to the engine to drive the engine in a range of high thermal efficiency, and cancels the engine torque generated by the engine with the power generation load of the motor generator, thereby making the torque transmitted from the transmission input shaft to the transmission output shaft zero.

3. 3. The control device for a hybrid vehicle according to claim 2, wherein the control unit, at the start of a shift in the transmission, shifts the driving state of the engine to a first engine operating point in a region where the engine speed is the same as before the start of the shift and where the engine thermal efficiency is higher than before the shift, and, before the shift is completed, shifts the driving state of the engine to a second engine operating point in a region where the engine speed is the same as the target engine speed after the shift and where the engine thermal efficiency is higher.

Images