Control device for vehicle

Abstract

To provide a technology capable of reducing a shift time when accelerator-on operation is performed during a downshift in an accelerator-off state.SOLUTION: An ECU 100 of a vehicle 1 controls a driving state of an engine 10 and a shift stage of an automatic transmission 30. The ECU 100 controls: a determination step of determining whether a downshift occurs in an accelerator-on state during execution of a downshift associated with an accelerator-off state; and a torque-up step of increasing torque on the basis of operation of an electronic control throttle of the engine when the downshift occurs in the accelerator-on state. In the torque-up step, a first throttle torque request amount in a first period up to a start of an inertia phase is made smaller than a second throttle torque request amount in a second period after the start of the inertia phase.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a control device for controlling a vehicle drive system equipped with an engine, an electronically controlled throttle (electronic throttle valve), an automatic transmission, a torque converter, a lock-up clutch, etc. This control device performs blipping control to temporarily increase the engine output rotation speed using the electronically controlled throttle during a manual power-off downshift. Furthermore, the control device engages the lock-up clutch based on the difference between the output rotation speed and the input rotation speed of the torque converter, which decreases after the start of blipping control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-196458 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can shorten the gear change time when the accelerator is applied during a downshift with the accelerator released. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a vehicle control device that controls the driving state of an engine and the gear positions of an automatic transmission, and that includes a determination step that determines whether or not a downshift will occur with the accelerator on when the accelerator is on during a downshift due to an accelerator release, and a torque-up step that increases torque based on the operation of an electronically controlled throttle of the engine before and after the start of an inertia phase of the automatic transmission if the determination step determines that a downshift will occur with the accelerator on, and in which the torque-up step makes a first throttle torque request amount in a first period before the start of the inertia phase smaller than a second throttle torque request amount in a second period after the start of the inertia phase. [Effects of the Invention]

[0006] According to one aspect, a vehicle control device can reduce the gear change time when the accelerator is pressed during a downshift with the accelerator released. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a vehicle having a control device according to an embodiment and its control system. [Figure 2] 1 is a table showing the relationship between the shift lever operation position of an automatic transmission and the combination of operations of hydraulic friction engagement elements. [Figure 3] 10 is a time chart showing a change in torque when the accelerator pedal is depressed during a downshift of an automatic transmission. [Figure 4] 10 is a flowchart illustrating a process performed when the accelerator is pressed during a downshift with the accelerator released. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] 1 is a diagram that schematically shows a vehicle 1 having a control device according to an embodiment and its control system. The vehicle 1 includes, as a driving device for driving, an engine 10, a torque converter 20, an automatic transmission 30, and a hydraulic control circuit 40. The vehicle 1 transmits rotation of an output shaft 31 of the automatic transmission 30 to a differential gear device 50, which rotates a pair of driving wheels 60. The vehicle 1 also includes an ECU (Electronic Control Unit) 100 as a control device that controls the driving device for driving.

[0010] The engine 10 is an internal combustion engine that has spark plugs (not shown) in its cylinders and generates rotational driving force by combustion of fuel (gasoline) injected into the cylinders. A crankshaft 11, which is the output shaft of the engine 10, is connected to a torque converter 20.

[0011] An intake pipe 12 of the engine 10 is provided with an electronically controlled throttle 13 that operates based on commands (electrical signals) from the ECU 100. The electronically controlled throttle 13 has a throttle valve 14 (butterfly valve) that adjusts the amount of intake air in the intake pipe 12 based on the control of the ECU 100. The electronically controlled throttle 13 changes the rotation speed of the engine 10 by sending an intake amount of air into the engine 10 that corresponds to the throttle opening of the throttle valve 14. The engine 10 also has a throttle opening sensor 15 that detects the throttle opening of the throttle valve 14. The throttle opening sensor 15 transmits information about the detected throttle opening to the ECU 10.

[0012] The rotational driving force of the engine 10 increases as the throttle opening of the throttle valve 14 increases. Basically, the ECU 100 increases the throttle opening as the driver of the vehicle 1 operates the accelerator pedal 70 (accelerator opening). Note that the ECU 100 can also change the throttle opening through control without depending on the operation of the accelerator pedal 70.

[0013] Accelerator pedal 70 is provided on the floor of the vehicle interior and is depressed by the driver's foot. Accelerator pedal 70 is provided with an accelerator position sensor 71 that detects the accelerator position, which is the amount of operation of accelerator pedal 70. Accelerator position sensor 71 transmits information about the detected accelerator position to ECU 100.

[0014] The torque converter 20 is a fluid power transmission device provided between the engine 10 and the automatic transmission 30, and transmits power via fluid. The torque converter 20 includes a pump impeller 21 on the input shaft side, a turbine runner 22 on the output shaft side, a stator 23 that amplifies torque, and a one-way clutch 24. The torque converter 20 transmits power via fluid between the pump impeller 21 and the turbine runner 22. The torque converter 20 is also provided with a lock-up clutch 25 that connects the input shaft side and the output shaft side of the torque converter 20 directly or in a slip state.

[0015] The pump impeller 21 is connected to the crankshaft 11 and rotates within the housing of the torque converter 20 in conjunction with the rotation of the crankshaft 11. The turbine runner 22 has a turbine shaft 221 at its center, and rotates the turbine shaft 221 under the action of the rotation of the pump impeller 21 and the stator 23. The turbine rotation speed, which is the rotation speed of the turbine shaft 221, is detected by a turbine rotation speed sensor 26. The turbine rotation speed sensor 26 transmits information about the detected turbine rotation speed to the ECU 100.

[0016] The lockup clutch 25 is a hydraulic friction clutch that is frictionally engaged by controlling the differential pressure between an engagement-side oil chamber (not shown) and a release-side oil chamber (not shown) by the hydraulic control circuit 40. The torque converter 20 can be in a disengaged state where the lockup clutch 25 is released, a semi-engaged state where the lockup clutch 25 is engaged with slippage, or an engaged state where the lockup clutch 25 is fully engaged. For example, when the lockup clutch 25 is engaged, the pump impeller 21 and turbine runner 22 rotate together, transmitting the rotational driving force of the engine 10 to the automatic transmission 30.

[0017] The automatic transmission 30 is configured as a stepped type having a plurality of predetermined gear stages (in other words, it is not a continuously variable transmission such as a CVT). The automatic transmission 30 has a plurality of hydraulic friction engagement elements and a planetary gear device. The automatic transmission 30 selectively establishes a plurality of gear stages by selectively engaging the plurality of friction engagement elements. An input shaft (not shown) of the automatic transmission 30 is connected to a turbine shaft 221 of the torque converter 20, while an output shaft 31 of the automatic transmission 30 is connected to a differential gear device 50.

[0018] The automatic transmission 30 switches the engagement of friction engagement elements based on the operation of the shift lever 72 by the driver. For example, the shift lever 72 has four shift lever operating positions: parking "P," reverse "R," neutral "N," and forward "D." One of the shift lever operating positions is selected by the driver manually operating the shift lever 72. The shift lever 72 is provided with a shift position sensor 73 that detects the operating position. The shift position sensor 73 transmits information about the shift lever operating position selected by the driver to the ECU 100.

[0019] Figure 2 is a table showing the relationship between the shift lever operating position of the automatic transmission 30 and the combination of operations of the hydraulic friction engagement elements. In Figure 2, "◯" indicates an engaged state, and "blank" indicates a released state. The automatic transmission 30 is equipped with, for example, four clutches C1 to C4 and two brakes B1 and B2 as friction engagement elements.

[0020] Clutches C1 to C4 have hydraulic servos made up of pistons, multiple friction engagement plates (friction plates and separator plates), oil chambers (engagement oil chambers and cancel oil chambers) to which hydraulic oil is supplied, return springs, seals, etc. Clutches C1 to C4 are configured as friction hydraulic clutches that use hydraulic servos to engage and disengage two rotating systems. Brakes B1 and B2 also have hydraulic servos made up of pistons, multiple friction engagement plates (friction plates and separator plates), oil chambers (engagement oil chambers and cancel oil chambers) to which hydraulic oil is supplied, return springs, seals, etc. Brakes B1 and B2 are configured as friction hydraulic brakes that non-rotatably engage (lock) the rotating system to the fixed system and release that lock.

[0021] The ECU 100 controls the hydraulic control valves in the hydraulic control circuit 40 based on information about the shift lever operating position of the shift lever 72 to switch between engagement and release of the clutches C1 to C4 and the brakes B1 and B2. When the shift lever is operated to the parking position (P), the ECU 100 switches the shift range to the parking range. In this case, the ECU 100 places the automatic transmission 30 in a neutral state, cutting off power transmission, and mechanically prevents rotation of the output shaft 31 of the automatic transmission 30 using a mechanical parking mechanism (not shown). When the shift lever is operated to the reverse (R) position, the ECU 100 switches the shift range to the reverse drive range. In this case, the ECU 100 engages the clutch C3 and the brake B2 to reverse the rotation direction of the output shaft 31. When the shift lever is operated to the neutral position (N), the ECU 100 switches the shift range to the neutral range. Then, ECU 100 cuts off power transmission within automatic transmission 30. When forward "D" is selected at the shift lever operating position, ECU 100 switches the shift range to a forward drive range. In this case, ECU 100 executes automatic shift control that automatically switches between multiple forward gears using clutches C1 to C4 and brakes B1 and B2 of automatic transmission 30. In particular, in the forward drive range, ECU 100 controls the engagement and release of clutches C1 to C4 and brakes B1 and B2 so that one of the multiple forward gears (eight gears in FIG. 2) is established in accordance with the accelerator pedal depression amount, vehicle speed, etc.

[0022] The hydraulic control circuit 40 is connected to the torque converter 20 (including the lock-up clutch 25), the automatic transmission 30, etc., with a mechanical oil pump (not shown) driven by the engine 10 as a hydraulic pressure supply source. The ECU 100 outputs a hydraulic pressure command to the hydraulic control circuit 40, which supplies appropriate hydraulic pressure to the torque converter 20, the lock-up clutch 25, the clutches C1 to C4, and the brakes B1 and B2 of the automatic transmission 30, etc., thereby controlling each drive. For example, when switching between gears in the forward driving range, the ECU 100 switches from the current gear to the target gear by having the hydraulic control circuit 40 supply hydraulic pressure to the target clutch or brake among the clutches C1 to C4 and the brakes B1 and B2.

[0023] The vehicle 1 also includes a vehicle speed sensor 61 that detects the rotational speed of the drive wheels 60 (in other words, the speed of the vehicle 1) on a shaft that connects the differential gear device 50 and the drive wheels 60. The vehicle speed sensor 61 transmits information about the detected vehicle speed to the ECU 100.

[0024] The ECU 100 is a computer (ECU: Electronic Control Unit) having a processor, memory, input / output interface, communication interface, etc. (not shown). The processor is an electronic circuit that combines one or more of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), a circuit made up of multiple discrete semiconductors, etc. The memory includes a main storage device made up of semiconductor memory such as RAM (Random Access Memory) and ROM (Read Only Memory), and an auxiliary storage device made up of a disk, semiconductor memory (flash memory), etc. The processor reads and processes programs stored in the memory, so that the ECU 100 executes various controls of the driving device.

[0025] Various signals are input to the ECU 100 from sensors provided in various parts of the vehicle 1. For example, the ECU 100 acquires information on the throttle opening of the electronically controlled throttle 13 detected by the throttle opening sensor 15, information on the turbine rotation speed detected by the turbine rotation speed sensor 26, information on the vehicle speed detected by the vehicle speed sensor 61, information on the accelerator opening detected by the accelerator opening sensor 71, information on the shift lever operating position detected by the shift position sensor 73, and the like.

[0026] The ECU 100 also outputs signals that control various devices of the vehicle 1. For example, the ECU 100 controls the driving state of the engine 10 by outputting a throttle signal that controls the opening and closing of the electronically controlled throttle 13, an ignition control signal that controls the ignition timing of the spark plugs of the engine 10, and the like. Furthermore, the ECU 100 outputs signals to the hydraulic control circuit 40, such as signals for driving solenoid valves in the hydraulic control circuit 40, as command signals for shift control of the automatic transmission 30 and the lock-up clutch 25.

[0027] When the shift lever is in the forward "D" position, the ECU 100 executes the forward driving range and performs automatic shift control to automatically switch between multiple forward gears based on the driving conditions of the vehicle 1 and the driving conditions of the driver. For example, the ECU 100 refers to an automatic shift map stored in memory and determines the gear of the automatic transmission 30 based on the throttle opening (or accelerator opening) and the vehicle speed (or turbine rotation speed). Furthermore, the ECU 100 controls the hydraulic control circuit 40 to establish the determined gear, thereby switching the engagement states of the clutches C1 to C4 and the brakes B1 and B2 of the automatic transmission 30.

[0028] Furthermore, the ECU 100 controls the engagement of the lockup clutch 25 based on the vehicle's running state. For example, the ECU 100 stores a lockup clutch engagement map (not shown) in advance in a memory. The lockup clutch engagement map associates a torque converter region in which the lockup clutch 25 is disengaged, a lockup slip region in which the lockup clutch 25 is partially engaged, and a lockup region in which the lockup clutch 25 is engaged with the throttle opening (or accelerator opening) and vehicle speed. The ECU 100 reads the lockup clutch engagement map and determines whether to perform disengagement control, partial engagement control, or engagement control based on the throttle opening and vehicle speed, and outputs a signal corresponding to the determination to the hydraulic control circuit 40. This allows the hydraulic control circuit 40 to appropriately control the state of the lockup clutch 25.

[0029] In the vehicle 1 configured as described above, the driver moves the shift lever 72 to the shift lever operation position for forward "D" to drive the vehicle 1 forward. In controlling the forward driving range, the ECU 100 automatically switches the gear of the automatic transmission 30 based on the throttle opening (or accelerator opening), the vehicle speed (or turbine rotation speed), etc., to drive the vehicle in an appropriate gear.

[0030] For example, the ECU 100 gradually reduces the vehicle speed by coasting when the driver is not depressing the accelerator pedal 70 (accelerator off). Also, the ECU 100 reduces the vehicle speed in a shorter time than coasting by braking when the driver is depressing the brake pedal (not shown). When decelerating by coasting or braking, the ECU 100 automatically reduces (downshifts) the gear position of the automatic transmission 30 based on the vehicle speed, turbine rotation speed, etc.

[0031] Incidentally, when the driver depresses the accelerator pedal 70 to switch the vehicle 1 to an accelerator-on state while the accelerator is off, such as during coasting or braking, the vehicle speed increases. However, when the automatic transmission 30 executes a downshift, hysteresis is taken into consideration and the control associated with the downshift is temporarily continued before the vehicle speed increases (re-acceleration, including upshifting). For this reason, if the downshift continues even when the accelerator pedal 70 is depressed, the driver may feel that the response of the driving operation of the vehicle 1 is poor. However, even if the torque of the engine 10 were to be suddenly increased in response to operation of the accelerator pedal 70, a mechanical shock (rattling) may occur in the driving drive device.

[0032] Therefore, when the driver presses accelerator pedal 70 (accelerator on state) during a downshift with the accelerator off, ECU 100 according to the embodiment adjusts the torque required of engine 10 to reduce mechanical shock and shorten the shift time. Specifically, ECU 100 varies the torque of engine 10 before and after the start of the inertia phase during a downshift of automatic transmission 30, regardless of the accelerator opening operated by the driver (in other words, driver-requested torque).

[0033] This control will be described in more detail below with reference to the time chart of Fig. 3. Fig. 3 is a time chart showing changes in torque when the accelerator pedal is depressed during a downshift of the automatic transmission 30. Note that Fig. 3 shows an example in which the automatic transmission downshifts from 3rd to 2nd, but it goes without saying that the same operation can be performed when downshifting from another gear.

[0034] During coasting or braking, the ECU 100 acquires the vehicle speed from the vehicle speed sensor 61 and / or the turbine rotation speed from the turbine rotation speed sensor 26 to determine whether or not to downshift the gear of the automatic transmission 30. For example, at time t1 in FIG. 3, the ECU 100 determines to downshift the gear from 3rd to 2nd.

[0035] Furthermore, ECU 100 manages the downshifting conditions as gear shift characteristics. For example, the gear shift characteristics include a driven downshift state, which is a downshift with the accelerator pedal 70 not depressed (accelerator off), and a driven downshift state, which is a downshift with the accelerator pedal 70 depressed (accelerator on). That is, ECU 100 recognizes a driven downshift, which is a downshift with the accelerator pedal off, at time t1 and manages the gear shift characteristics. After the start of time t1, ECU 100 drives engine 10 in a state where the ignition timing of engine 10 is not retarded (torque down is an inactive value) and the air intake amount of electronically controlled throttle 13 is also substantially constant (torque up is an inactive value).

[0036] Furthermore, during a driven downshift, the ECU 100 performs a determination process to determine whether the driver has depressed the accelerator pedal 70, thereby turning the accelerator on. For example, at time t2 in FIG. 3 when the automatic transmission 30 is downshifting, the ECU 100 detects that the driver has turned the accelerator on. In other words, the ECU 100 recognizes that the accelerator is on by receiving a signal indicating a gradual increase in accelerator pedal position from the accelerator position sensor 71 as accelerator pedal position information. At this timing, the ECU 100 increases the driver-requested torque that the driver requests from the engine 10 based on the accelerator pedal position. Therefore, the ECU 100 increases the throttle torque request amount of the electronically controlled throttle 13 in accordance with the driver-requested torque, and the engine 10 increases the actual torque in proportion to the increase in the intake air volume. However, since the driver-requested torque is small around time t2, the throttle torque request amount of the electronically controlled throttle 13 is also small.

[0037] At time t3 when the accelerator opening has increased to a certain extent, the ECU 100 determines that the accelerator is on during downshifting, in other words, that the shift has switched from a driven downshift to a driving downshift. In other words, at this timing, the ECU 100 switches the shift characteristics it manages from a driven downshift to a driving downshift (a downshift with the accelerator on).

[0038] The ECU 100 adjusts the torque requirements required for driving the engine 10 when shifting down from the driven state to the driving state. Specifically, at time t3, the ECU 100 requests a torque reduction by retarding the ignition timing of the engine 10. Hereinafter, the torque requirement for this torque reduction by retarding the ignition timing is referred to as a retard torque requirement. The retard torque requirement is a torque amount requested when the ECU 100 sends an ignition timing command to the engine 10 and can be converted into an ignition timing retard. The retard torque requirement is set according to the mechanical structures of the engine 10, the torque converter 20, and the automatic transmission 30. For example, the ECU 100 stores map information indicating the relationship between the retard torque requirement and a speed change that indicates the possibility of backlash occurring in the mechanical structures of the torque converter 20 and the automatic transmission 30 as the actual torque of the engine 10 changes. When performing a torque reduction by retarding the ignition timing, the ECU 100 sets the retard torque requirement based on the map information.

[0039] The retard torque request is a value that allows the actual torque of the engine 10 to be controlled even if the ignition timing of the engine 10 is retarded, and does not cause mechanical shock (rattling) in the engine 10, the torque converter 20, and the automatic transmission 30. The ECU 100 also minimizes the retard torque request at time t3 and then gradually increases it to a predetermined constant value. As a result, the ECU 100 can gradually advance the retard angle in accordance with the actual torque during the transitional period in which the ignition timing of the engine 10 is retarded, thereby appropriately controlling the actual torque of the engine 10.

[0040] At time t3, the ECU 100 starts a torque-up process to increase the torque on the electronically controlled throttle 13 side. Hereinafter, the torque demand of the electronically controlled throttle 13 will be referred to as the throttle torque demand. The throttle torque demand is the amount of torque that the ECU 100 demands when sending a command for the throttle opening to the electronically controlled throttle 13, and can be converted into the intake amount of the throttle valve 14.

[0041] The required throttle torque is preferably set to a limit value (misfire limit value) at which the torque can be maximized without causing a misfire in the engine 10, whose ignition timing has been retarded by retarding the ignition timing. That is, when the ignition timing of the engine 10 is retarded by retarding the ignition timing, the likelihood of misfire increases if the amount of intake air from the electronically controlled throttle 13 increases. In response to this, the ECU 100 can sufficiently increase the torque on the electronically controlled throttle 13 side without causing a misfire in the engine 10 by setting the required throttle torque to the misfire limit value at which a misfire does not occur.

[0042] Furthermore, the ECU 100 sets the requested throttle torque to a value greater than the torque associated with the driver-requested torque. For example, even if the driver-requested torque is 40 N, the ECU 100 sets the requested throttle torque to 80 N or the like. By setting the requested throttle torque to be greater than the driver-requested torque in this way, the amount of torque increased by the electronically controlled throttle 13 can be sufficiently increased. In other words, an increase in the requested throttle torque increases the amount of air intake from the electronically controlled throttle 13 in the engine 10, making it easier for the actual torque to increase.

[0043] However, in the torque-up process, the first throttle torque request amount during a first period before the inertia phase of the automatic transmission 30 begins is set smaller than the second throttle torque request amount during a second period after the inertia phase begins. As a result, during the first period, the actual torque of the engine 10 changes at a torque corresponding to the retard torque request amount. Even if the ignition timing is delayed according to the retard torque request amount during the first period, the engine 10 can preliminarily increase the torque on the electronically controlled throttle 13 side by using the set throttle torque request amount while avoiding misfires.

[0044] After time t1, the automatic transmission 30 gradually shifts gears from 3rd to 2nd based on the supply of hydraulic pressure from the hydraulic control circuit 40, and continues this shifting of gears even when the shift changes from driven downshift to driven downshift at time t3. For example, during the shifting of gears in the automatic transmission 30, the period from time t1 to time t4 is a torque phase in which the disengaged clutch (3rd) mainly receives the driving force of the engine 10 (turbine shaft 221 of the torque converter 20). On the other hand, during the shifting of gears in the automatic transmission 30, the period from time t4 to time t6 is an inertia phase in which the engaged clutch (2nd) mainly receives the driving force of the engine 10. The automatic transmission 30 reduces the mechanical shock of the shifting of gears by gradually increasing the engagement of the engaged clutch using hydraulic pressure from the hydraulic control circuit 40.

[0045] That is, time t4 is the time point at which the torque phase and the inertia phase are switched over. The ECU 100 recognizes the torque phase and the inertia phase as a state quantity of the automatic transmission 30 based on the turbine rotation speed (rotational speed) of the turbine shaft 221. For example, the ECU 100 determines whether the inertia phase is executed (started) or not by setting an inertia phase flag (changing it from 0 to 1) based on the turbine rotation speed of the turbine rotation speed sensor 26.

[0046] The ECU 100 performs a torque-up process for the electronically controlled throttle 13 in conjunction with the start of a drive downshift. However, even after starting the torque-up process, the ECU 100 also performs the aforementioned retard torque down process during a first period (time points t3 to t4) before the start of the inertia phase. That is, during the first period, the ECU 100 outputs a retard torque request amount that is lower than the invalid value to retard the engine 10, and outputs a first throttle torque request amount that is increased to an extent that the engine 10 does not misfire, thereby creating a state in which the actual torque of the engine 10 is likely to increase. The retard torque request amount and the first throttle torque request amount enable the vehicle 1 to smoothly increase the actual torque of the engine 10 after the start of the inertia phase while suppressing mechanical shocks of the driving drive system.

[0047] Then, at time t4, when the inertia phase flag is raised, the ECU 100 ends the retarded torque reduction of the engine 10. Also, at time t4, the ECU 100 increases the throttle torque requirement of the electronically controlled throttle 13 from the first throttle torque requirement to the second throttle torque requirement. The second throttle torque requirement is greater than the first throttle torque requirement. However, because the throttle torque requirement of the engine 10 has been increased by time t4, the amount of torque increase in the second period is reduced.

[0048] During the second period after the start of the inertia phase, the ignition timing of the engine 10 advances (returns to the original state) and the throttle torque demand of the electronically controlled throttle 13 increases, allowing the actual torque to increase smoothly. In other words, the actual torque of the engine 10 increases to the misfire limit of the engine 10 according to the retard torque demand and the first throttle torque demand, and then increases from time t4 to the second throttle torque demand in a short period of time. As a result, the automatic transmission 30 can significantly shorten the period of the inertia phase during a downshift.

[0049] Furthermore, at time t5 before the end of the inertia phase, the ECU 100 performs torque reduction for retarding and also reduces the torque of the electronically controlled throttle 13. At this time t5, the inertia phase of the downshift is almost over. At this stage, the actual torque of the engine 10 is reduced in a short time in accordance with the required amount of retard torque for the torque reduction for retarding, thereby mitigating the mechanical shock that occurs immediately after the automatic transmission 30 changes gears.

[0050] Then, the automatic transmission 30 completes the downshift at time t6. At the end of the downshift, the ECU 100 restores the retard angle of the engine 10, thereby enabling smooth running in 2nd gear. In particular, when the speed increases after the driver presses the accelerator, the speed increases smoothly after time t6, making it possible to, for example, transition from a downshift to an upshift in a short time.

[0051] The control device (ECU 100) of the vehicle 1 according to the embodiment is basically configured as described above, and the processing flow thereof will be described below with reference to Fig. 4. Fig. 4 is a flowchart illustrating processing when the accelerator is pressed during a downshift with the accelerator released.

[0052] The ECU 100 automatically downshifts the automatic transmission 30 when coasting or braking with the accelerator released. At this time, the ECU 100 determines whether a driven downshift is to be performed based on accelerator opening information from the accelerator opening sensor 71 (step S101). If the accelerator opening remains at 0° (accelerator released), the ECU 100 sets the gear shift characteristics to a driven downshift (step S101: YES) and proceeds to step S102. On the other hand, if the accelerator is applied before a downshift (step S101: NO), the process proceeds to a process of increasing the vehicle speed based on the accelerator opening, and therefore a downshift is not performed at all. Therefore, the ECU 100 ends this processing flow.

[0053] In step S102, the ECU 100 starts a driven downshift and transitions to an operation of lowering (downshifting) the gear position of the automatic transmission 30. In this case, the automatic transmission 30 first executes a torque phase in which the rotational driving force is mainly transmitted by the release clutch side, while gradually weakening the engagement of the release clutch side.

[0054] Then, while the driven downshift is being performed, the ECU 100 monitors the inertia phase flag of the automatic transmission 30 and determines whether the inertia phase flag is off (step S103). When the inertia phase flag is on, the rotational driving force is mainly transmitted by the engaged clutch during the driven downshift. Even if the driver depresses the accelerator pedal 70 after the inertia phase starts, the effect of increasing the torque on the electronically controlled throttle 13 side is small. Therefore, after the inertia phase start flag is on (step S103: NO), the ECU 100 ends this processing flow without performing the torque increase process for the electronically controlled throttle 13. On the other hand, if the inertia phase start flag is off (step S103: YES), the ECU 100 proceeds to step S104.

[0055] In step S104, ECU 100 monitors the accelerator opening and determines whether the driver's depression of accelerator pedal 70 has resulted in a transition from a driven downshift to a driving downshift. If the accelerator pedal 70 is not depressed (accelerator off) (step S104: NO), ECU 100 returns to step S103 and repeats the same processing thereafter. On the other hand, if the accelerator pedal 70 is depressed (accelerator on) (step S104: YES), ECU 100 proceeds to step S105.

[0056] In step S105, the ECU 100 performs a torque reduction by retarding the angle and also performs a torque increase process for the electronically controlled throttle 13. That is, the ECU 100 outputs a retard torque request amount to the engine 10 and also outputs a first throttle torque request amount to the electronically controlled throttle 13. The engine 10 retards the ignition timing of the engine 10 based on the retard torque request amount. This suppresses mechanical shock (rattle) in the driving system. Furthermore, the automatic transmission 30 outputs the first throttle torque request amount to the electronically controlled throttle 13 to ensure the responsiveness of the electronically controlled throttle 13 in the inertia phase. This allows the vehicle 1 to increase the torque of the electronically controlled throttle 13 while suppressing misfires during the first period before the start of the inertia phase of the automatic transmission 30.

[0057] Then, the ECU 100 monitors the inertia phase flag of the automatic transmission 30 and determines whether the inertia phase flag has been set (step S106). If the inertia phase flag is off (step S106: NO), the ECU 100 continues this monitoring, whereas if the inertia phase flag is on (step S106: YES), the ECU 100 proceeds to step S107.

[0058] With the start of the inertia phase, the ECU 100 stops outputting the retard torque request amount and outputs a further torque increase (second throttle torque request amount) to the electronically controlled throttle 13 (step S107). This allows the vehicle 1 to increase the actual torque of the engine 10 in a short time while the inertia phase is being executed in the downshift of the automatic transmission 30. As a result, it is possible to shorten the entire inertia phase period, and ultimately the entire downshift period.

[0059] During the execution of the inertia phase, the ECU 100 determines whether the inertia phase is about to end (step S108). If the inertia phase is not about to end (step S108: NO), the ECU 100 continues this monitoring while the inertia phase continues, but if the inertia phase is about to end (step S108: YES), the ECU 100 proceeds to step S109.

[0060] In step S109, the ECU 100 ends the torque-up process of the electronically controlled throttle 13 (sets the throttle torque request amount to zero), thereby reducing the actual torque of the engine 10, which has been increasing during the inertia phase. At this time, the ECU 100 also retards the angle of the engine 10 to reduce the torque, thereby reducing the actual torque of the engine 10. This allows the vehicle 1 to smoothly perform the next process when the downshift is completed.

[0061] As described above, the control device (ECU 100) according to this embodiment appropriately adjusts the torque of the engine 10 in accordance with the state of the automatic transmission 30 when the accelerator is turned on during a downshift with the accelerator off. This enables the vehicle 1 to reduce mechanical shock to the driving drive system and reduce the shift time of the automatic transmission 30, thereby mitigating hesitation. In particular, when the gear ratio difference (synchronous rotation difference) between gear stages in the automatic transmission 30 is large, the shift time required for a downshift tends to be long, but the vehicle 1 can shorten the shift time as much as possible by performing the above processing.

[0062] The control device (ECU 100) of the vehicle 1 according to the present disclosure is not limited to the above embodiment, and various modifications are possible. For example, the ECU 100 according to the embodiment is configured not to perform the torque-up process of the electronically controlled throttle 13 when the accelerator is turned on after the inertia phase has started. However, the ECU 100 may also be configured to perform the torque-up process of the electronically controlled throttle 13 even when the accelerator is turned on after the inertia phase has started.

[0063] The technical concept and effects of the present invention explained in the above embodiment will be described below.

[0064] One aspect of the present disclosure is a control device (ECU 100) of a vehicle 1 that controls the driving state of an engine 10 and the gear stages of an automatic transmission 30, and controls the following: a determination process that determines whether a downshift will occur with the accelerator on when the accelerator is on during a downshift due to accelerator release; and a torque-up process that increases torque based on the operation of an electronically controlled throttle 13 of the engine 10 before and after the start of the inertia phase of the automatic transmission 30 if the determination process determines that a downshift will occur with the accelerator on; and in the torque-up process, the first throttle torque requirement in a first period before the start of the inertia phase is made smaller than the second throttle torque requirement in a second period after the start of the inertia phase.

[0065] According to the above, the control device (ECU 100) of the vehicle 1 makes the second throttle torque request amount in the second step after the start of the inertia phase greater than the first throttle torque request amount before the start of the inertia phase during the torque-up process of the electronically controlled throttle 13. This allows the control device to appropriately increase torque by the first throttle torque request amount before the start of the inertia phase, thereby shortening the gear change time after the start of the inertia phase. Therefore, when the accelerator is depressed during a downshift, the control device can shorten the gear change time and improve the driver's operational comfort.

[0066] Furthermore, a retard is generated to delay the ignition timing of the engine 10 during the first period, and the first throttle torque requirement is set based on the retard torque requirement accompanying the retard of the engine 10. This allows the vehicle 1 to set the first throttle torque requirement according to the retard torque requirement of the engine 10, and to appropriately increase the torque of the electronically controlled throttle 13.

[0067] Furthermore, the first throttle torque requirement is set based on a misfire limit value that prevents misfire in the retarded engine 10 due to the intake air amount of the electronically controlled throttle 13. This allows the control device (ECU 100) to increase the torque of the electronically controlled throttle 13 without causing misfire in the engine 10.

[0068] The first throttle torque requirement is greater than the driver's required torque when the driver presses the accelerator pedal, which allows the control device (ECU 100) to stably increase the torque by the electronically controlled throttle 13 even when the driver's accelerator pedal opening is small.

[0069] Furthermore, with the start of the second period, the retarded ignition timing of the engine 10 is returned, thereby enabling the control device (ECU 100) to obtain high torque in the second period when the inertia phase starts.

[0070] The inertia phase is a state in which the engaged clutch mainly transmits rotational driving force during a downshift of the automatic transmission 30, and during the torque-up process, the timing of switching the inertia phase is recognized based on the rotation speed of the shaft (turbine shaft 221) connected to the input shaft of the automatic transmission. This allows the control device (ECU 100) to appropriately determine the start timing of the inertia phase and smoothly switch between the throttle torque request amount and the retard torque request amount.

[0071] In addition, in the determination process, if the accelerator is turned on before the inertia phase starts, the torque-up process is performed, but if the accelerator is turned on after the inertia phase starts, the torque-up process is not performed. In this way, by not performing the torque-up process after the inertia phase starts, the control device (ECU 100) can simplify the control.

[0072] Furthermore, in the torque-up process, the second throttle torque request amount is reduced before the end of the inertia phase, which allows the control device (ECU 100) to appropriately end the torque-up process in accordance with the automatic transmission 30, and allows the vehicle 1 to smoothly accelerate again, etc.

[0073] The control device (ECU 100) according to the embodiment disclosed herein is illustrative in all respects and is not limiting. The embodiment can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0074] 1 vehicle 10 Engine 13 Electronically controlled throttle 30 Automatic transmission 70 Accelerator pedal 100 ECU 221 Turbine shaft

Claims

1. A vehicle control device that controls the driving state of an engine and the gear position of an automatic transmission, a determination step of determining whether or not a downshift will occur in the accelerator-on state when the accelerator is turned on during a downshift due to an accelerator-off state; a torque-up step of increasing torque based on operation of an electronically controlled throttle of the engine before and after a start of an inertia phase of the automatic transmission when a downshift is determined in the accelerator-on state by the determination step; In the torque-up process, a first throttle torque request amount in a first period before the start of the inertia phase is made smaller than a second throttle torque request amount in a second period after the start of the inertia phase. Vehicle control device.

2. causing a retard that retards the ignition timing of the engine during the first period; the first throttle torque requirement is set based on a retard torque requirement associated with a retard of the engine; The vehicle control device according to claim 1 .

3. the first throttle torque requirement is set based on a misfire limit value at which the retarded engine does not misfire due to the intake amount of the electronically controlled throttle; The vehicle control device according to claim 2.

4. The first throttle torque request amount is a torque greater than a driver request torque when the driver presses the accelerator pedal. The vehicle control device according to claim 2.

5. With the start of the second period, the retarded ignition timing of the engine is returned. The vehicle control device according to claim 2.

6. The inertia phase is a state in which the engagement clutch side mainly transmits rotational driving force during a downshift of the automatic transmission, In the torque-up process, a timing of switching the inertia phase is recognized based on a rotation speed of a shaft connected to an input shaft of the automatic transmission. The vehicle control device according to any one of claims 1 to 5.

7. In the determination step, when the accelerator is turned on before the inertia phase starts, the torque-up step is performed, whereas when the accelerator is turned on after the inertia phase starts, the torque-up step is not performed. The vehicle control device according to any one of claims 1 to 5.

8. In the torque-up process, the second throttle torque request amount is reduced before the end of the inertia phase. The vehicle control device according to any one of claims 1 to 5.

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