JP2022164489A - Controller for vehicle - Google Patents

Abstract

To provide a controller for vehicle capable of suppressing fuel economy from decreasing while improving engine stall resistance.SOLUTION: An electronic controller 90 for a vehicle 10 that executes, once it is determined that an engine stall may occur during execution of fuel cutting, fuel recovery after starting release control to completely release a lock-up clutch 18 of a torque converter 18. comprises: a setting part 90b which sets execution timing of the fuel recovery to a predetermined first point tx of time in advance; and a correction part 90e which corrects the execution timing to a predetermined second point ty of time earlier than the predetermined first point tx of time when it is determined that an engine rotating speed decrease quantity ΔNe in a predetermined period T after the setting of the execution timing by the setting part 90b is equal to or larger than a predetermined decrease quantity ΔNe_jdg.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a control system for a vehicle equipped with an engine and a torque converter provided between the engine and drive wheels and having a lockup clutch, and more particularly to fuel recovery for resuming fuel supply to the engine. .

In a vehicle equipped with an engine and a torque converter having a lockup clutch disposed between the engine and drive wheels, coasting (coasting) in which the accelerator pedal is not depressed, for example, is used to suppress fuel consumption. There is known a technology for executing a fuel cut that stops the supply of fuel to the engine while the vehicle is running. Then, when the lockup clutch is in the disengaged (OFF) state, the engine speed is compared with a predetermined threshold for the disengaged state of the lockup clutch, and the engine speed is determined to be lower than the threshold. Vehicle controllers are known that perform fuel recovery to restart the supply of fuel to the engine when the V becomes low. For example, the one described in Patent Document 1 is it.

JP-A-2013-60048

In the vehicle control device described in Patent Document 1, fuel recovery is executed when the engine rotation speed is less than the threshold value, but when the engine rotation speed drops more rapidly than expected, the engine stalls (stops the engine). It may occur. If the threshold value is set high in order to suppress the occurrence of this engine stall, fuel recovery will be executed early when the engine speed is high, resulting in a decrease in fuel efficiency.

F. The present invention was made against the background of the above circumstances, and an object thereof is to provide a control device for a vehicle capable of suppressing a decrease in fuel consumption while improving engine stall resistance.

The gist of the first invention is applied to a vehicle equipped with an engine and a torque converter provided between the engine and drive wheels and having a lockup clutch, and cuts the fuel of the engine. A control device for a vehicle that, when it is determined that there is a possibility that an engine stall may occur when the lockup clutch is in a fully released state, executes fuel recovery after starting release control to bring the lockup clutch into a completely released state, comprising: (a (b) a setting unit that presets the execution timing of the fuel recovery to a predetermined first point in time; and a correction unit that corrects the execution timing to a predetermined second point in time that is earlier than the predetermined first point in time when it is determined that the execution timing is .

According to the first invention, (a) a setting unit that presets the execution timing of the fuel recovery to a predetermined first point in time; a correction unit that corrects the execution timing to a predetermined second point in time that is earlier than the predetermined first point in time when it is determined that the amount of decrease in rotational speed is equal to or greater than a predetermined amount. When the amount of decrease in engine rotation speed is greater than or equal to a predetermined amount, that is, in a situation where there is a risk of engine stall, the fuel recovery execution timing is corrected to be earlier (=second time) than in other situations. Therefore, engine stall resistance is improved. When the amount of decrease in the rotational speed of the engine is less than a predetermined amount, that is, in a situation in which there is no risk of engine stalling, the time point (=first time point) at which fuel recovery is executed is later than in other situations. Therefore, a decrease in fuel consumption is suppressed. Therefore, the deterioration of fuel efficiency is suppressed while the engine stall resistance is improved.

According to the second invention, in the first invention, when the shock occurring in the vehicle is predicted to be within an allowable range when the fuel recovery is performed at the predetermined second time point, the correction unit and correcting the execution timing to the predetermined second point in time. In this way, fuel recovery is executed at the predetermined second point in time at which the shock occurring in the vehicle is predicted to be within the allowable range. the occurrence of shock is suppressed.

According to the third invention, in the second invention, when it is predicted that the lockup clutch is disengaging at the predetermined second time point and the rotation speed difference of the torque converter is equal to or greater than a predetermined difference, the fuel It is predicted that the shock produced by the vehicle will exceed an acceptable range if recovery is performed at the second predetermined time. As described above, when the lockup clutch is disengaged (half-engaged during switching from the fully engaged state to the fully disengaged state) and the rotational speed difference of the torque converter is equal to or greater than a predetermined difference, the vehicle is predicted to exceed the allowable range, the fuel recovery execution timing corrected by the correction unit is set to the timing at which the occurrence of shock in the vehicle is suppressed.

1 is a schematic configuration diagram of a vehicle equipped with an electronic control unit according to an embodiment of the present invention, and a functional block diagram for explaining main parts of control functions of the electronic control unit; FIG. FIG. 2 is an example of a flow chart for explaining the control operation of the electronic control unit shown in FIG. 1; FIG. FIG. 3 is an example of a time chart when the flowchart of FIG. 2 is executed; FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, etc. of each part are not necessarily drawn accurately.

FIG. 1 is a schematic configuration diagram of a vehicle 10 equipped with an electronic control unit 90 according to an embodiment of the present invention, and a functional block diagram for explaining essential control functions of the electronic control unit 90. As shown in FIG.

The vehicle 10 includes an engine 12 , a power transmission device 14 , a pair of drive wheels 32 , a hydraulic control circuit 38 and an electronic controller 90 .

The engine 12 is a driving source of the vehicle 10, and is an internal combustion engine such as a gasoline engine or a diesel engine. The electronic control unit 90 controls the engine control unit 40 such as a throttle actuator, a fuel injection device, and an ignition device provided in the vehicle 10 to control the operating state (start, run, stop) of the engine 12. be done.

The power transmission device 14 includes a torque converter 18, an automatic transmission 22, and the like in order from the engine 12 side within a transmission case 16 as a non-rotating member. The power transmission device 14 also includes a propeller shaft 26 connected to an output shaft 24 that is an output rotating member of the automatic transmission 22, a differential gear 28 connected to the propeller shaft 26, and a pair of gears connected to the differential gears 28. An axle 30 and the like are provided.

Torque converter 18 is a well-known hydrodynamic power transmission device. In the torque converter 18, a pump impeller 18p is connected to the engine 12, and a turbine impeller 18t is connected to an automatic transmission 22 via an input shaft 20 corresponding to an output side member of the torque converter 18. The torque converter 18 includes a known lockup clutch 18c that directly connects the pump impeller 18p and the turbine impeller 18t. The lockup clutch 18c is, for example, a hydraulic friction clutch (wet clutch), and can mechanically connect the power transmission path between the engine 12 and the drive wheels 32 directly. The torque converter 18 includes an engagement-side oil chamber 18on supplied with hydraulic pressure for engaging the lockup clutch 18c, and a release-side oil chamber 18off supplied with hydraulic pressure for disengaging the lockup clutch 18c. The engagement-side oil chamber 18on and the release-side oil chamber 18off function as hydraulic actuators that control the connection and disconnection of the lockup clutch 18c. An oil pump 36 is connected to the pump impeller 18p. The oil pump 36 is a mechanical pump that is driven to rotate by the engine 12 to pump hydraulic oil to the hydraulic control circuit 38 for executing gear shift control of the automatic transmission 22 and connection/disengagement control of the lockup clutch 18c. It's the oil pump. The lockup clutch 18c is controlled by a hydraulic control circuit 38 provided in the vehicle 10 using the hydraulic pressure generated by the oil pump 36 as a source pressure. Thus, the present invention applies to a vehicle 10 having an engine 12 and a torque converter 18 disposed between the engine 12 and drive wheels 32 and having a lockup clutch 18c.

The automatic transmission 22 is a transmission arranged on a power transmission path between the torque converter 18 and the drive wheels 32 to transmit power from the engine 12 to the drive wheels 32 . The automatic transmission 22 is, for example, a known planetary gear type multi-stage transmission capable of selectively establishing a plurality of gear stages having different gear ratios γ (=input shaft rotation speed Nin [rpm]/output shaft rotation speed Nout [rpm]). machine. For example, the automatic transmission 22 selectively establishes a gear stage selected by a combination of disengagement/engagement states of each disengagement device (hydraulic friction engagement device for clutches and brakes) in the automatic transmission 22 . The input shaft rotation speed Nin is the rotation speed of the input shaft 20 and the output shaft rotation speed Nout is the rotation speed of the output shaft 24 .

The differential gear 28 is a well-known differential gear that transmits a driving force while appropriately giving differential rotation to a pair of axles 30 connected to a pair of driving wheels 32 respectively.

Power output from the engine 12 is transmitted to a pair of drive wheels 32 via a torque converter 18, an input shaft 20, an automatic transmission 22, an output shaft 24, a propeller shaft 26, a differential gear 28, and a pair of axles 30. be. The vehicle 10 is an FR (front engine/rear drive) vehicle.

The hydraulic control circuit 38 generates control hydraulic pressure for connecting/disconnecting clutches and brakes, which are connecting/disconnecting devices provided in the automatic transmission 22, based on a hydraulic control signal Sp input from the electronic control unit 90, for example. , to the actuators of each disconnecting device. Further, the hydraulic control circuit 38 generates a clutch hydraulic pressure Plu [Pa], which is a control hydraulic pressure for connecting and disconnecting the lockup clutch 18c of the torque converter 18, based on a hydraulic control signal Sp input from the electronic control unit 90, for example. and output to the actuator of the lockup clutch 18c. For example, the clutch oil pressure Plu is the differential pressure (=engagement pressure - release pressure) between the engagement pressure supplied to the engagement side oil chamber 18on and the release pressure supplied to the release side oil chamber 18off.

The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, and an input/output interface. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 90 controls the operating state of the engine 12, the connection/disconnection control of the lockup clutch 18c, and the shift control of the automatic transmission 22 (for example, the connection/disconnection that selectively establishes the gear stage of the automatic transmission 22). device connection/disconnection control), etc. The electronic control device 90 corresponds to the "control device" in the present invention.

The electronic control unit 90 includes various sensors provided in the vehicle 10 (for example, engine rotation speed sensor 50, input shaft rotation speed sensor 52, output shaft rotation speed sensor 54, accelerator opening sensor 56, throttle valve opening sensor, etc.). 58, oil pressure sensor 60, etc.) based on the detected value (e.g., engine rotation speed Ne [rpm], input shaft rotation speed equal to turbine rotation speed Nt [rpm], which is the rotation speed of the turbine wheel 18t) Nin [rpm], output shaft rotation speed Nout [rpm], which is the rotation speed of the output shaft 24 corresponding to the vehicle speed V [km/h], accelerator opening as an acceleration operation amount representing the magnitude of the acceleration operation by the driver θacc [%], throttle valve opening θth [%] which is the opening of the electronic throttle valve, clutch oil pressure Plu [Pa] supplied to the actuator of the lockup clutch 18c, etc.) are input. The input shaft rotation speed sensor 52 also functions as a turbine rotation speed sensor.

From the electronic control unit 90, various command signals (e.g., engine control signal Se for controlling the engine 12, automatic transmission Hydraulic control signal Sp for speed change control of the gear 22 and connection/disengagement control of the lockup clutch 18c, etc.) are respectively output. For example, the engine control signal Se includes a fuel supply stop signal, and the electronic control unit 90 turns on the fuel supply stop signal to cause the fuel injection device to stop supplying fuel to the engine 12, thereby stopping the fuel supply. Turning off the signal causes the fuel injector to supply fuel to the engine 12 . That is, when the fuel supply stop signal is turned on, fuel cut is executed to stop fuel injection, resulting in a fuel cut-on state, and when the fuel supply stop signal is turned off, fuel cut is not executed. The fuel is cut off.

The electronic control unit 90 functionally includes a return determination section 90a, a setting section 90b, a decrease determination section 90c, a shock prediction section 90d, a correction section 90e, and a return execution section 90f.

The return determining unit 90a determines whether or not to execute fuel recovery, ie, whether or not to restore from the fuel cut-on state to the fuel cut-off state because there is a risk of engine stall. For example, when the engine rotation speed Ne is less than a predetermined rotation speed value Ne_jdg or when the vehicle speed V is less than a predetermined vehicle speed value V_jdg [km/h], fuel recovery may be performed as there is a risk of engine stall. decided to run. Each of the predetermined rotation speed value Ne_jdg and the predetermined vehicle speed value V_jdg is a value determined in advance experimentally or by design, assuming that the engine stall may occur when the fuel cut of the engine 12 is executed. be.

Here, the predetermined specific state is defined as the actual rotational speed difference ΔLU (=Nt−Ne) [rpm] of the torque converter 18, which is assumed to be predetermined over time during execution of the fuel cut. A vehicle state in which ΔLU is large is referred to. For example, the vehicle 10 may be in a predetermined specific state due to the responsiveness of the brake operation by the driver during execution of the fuel cut or the responsiveness of control by the clutch oil pressure Plu for the connection/disengagement control of the lockup clutch 18c. Fuel recovery is performed with good responsiveness to a control signal for resuming fuel supply by the electronic control unit 90 . On the other hand, since the release control of the lockup clutch 18c is hydraulic control, the release control of the lockup clutch 18c is less responsive to the release control signal from the electronic control unit 90 than the fuel recovery. Therefore, the actual operating state (completely engaged state, half-engaged state, completely released state) of the lockup clutch 18c may differ from the assumed state controlled by the electronic control unit 90 . It should be noted that the predetermined normal state refers to a vehicle state that is not the above-described predetermined specific state.

When the return determination unit 90a determines to execute fuel recovery, the setting unit 90b determines the start time and release time of the release control to shift the lockup clutch 18c from the semi-engaged state (slip state) to the fully released state. The end time of control is set, and the execution timing of fuel recovery is set at a predetermined first time point tx. A predetermined first time point tx, which is the execution timing of fuel recovery, is set at a time after the release control of the lockup clutch 18c is started. The execution timing of fuel recovery is the timing of returning from the fuel cut-on state to the fuel cut-off state, and the timing of restarting fuel supply to the engine 12 . For example, the setting unit 90b changes the clutch oil pressure Plu from the start time of the release control of the lockup clutch 18c to the end time of the release control according to the deceleration of the vehicle 10 (decrease amount of the vehicle speed V per unit time). Set the fall speed. Preferably, the predetermined first time point tx, which is the execution timing of fuel recovery, is set to be the same as the end time of release control of the lockup clutch 18c. This suppresses the occurrence of a shock caused by a torque step during the execution of fuel recovery, and suppresses the decrease in the engine rotation speed Ne before the execution of fuel recovery. (difficult to use) is suppressed. For example, the predetermined first time point tx is based on a map in which the relationship between the vehicle speed V, gear ratio γ, deceleration, and the predetermined first time point tx in a normal state is predetermined experimentally or by design. calculated as

At the release control start time set by the setting unit 90b, the return execution unit 90f starts release control of the lockup clutch 18c. Further, the return executing section 90f controls the lockup clutch 18c so that the release control of the lockup clutch 18c is completed at the end time of the release control set by the setting section 90b.

The decrease determination unit 90c determines that the engine rotation speed decrease amount ΔNe [rpm], which is the decrease amount of the engine rotation speed Ne in a predetermined period T [ms] after the execution timing is set by the setting unit 90b, is determined to be a predetermined decrease amount ΔNe_jdg [rpm]. It is determined whether or not the above is satisfied. The predetermined time period T is a predetermined time period after the execution timing is set by the setting unit 90b. The predetermined time period T starts after the execution timing is set by the setting unit 90b. The end is prior to the predetermined first time point tx. The predetermined decrease amount ΔNe_jdg is the engine rotation speed during a predetermined period T, which is predetermined experimentally or by design as a possibility that an engine stall may occur due to a specific state when the fuel cut of the engine 12 is being executed. This is the lower limit value of the speed reduction amount ΔNe. Note that, if the vehicle 10 is in a normal state, the engine rotation speed decrease amount ΔNe during the predetermined period T is less than the predetermined decrease amount ΔNe_jdg [rpm].

The shock prediction unit 90d predicts whether or not the shock that will occur in the vehicle 10 when the fuel recovery is executed at a predetermined second time point ty that is earlier than the predetermined first time point tx is within an allowable range. Details of the predetermined second time point ty will be described later. For example, the lock-up clutch 18c is disengaged (semi-engaged during switching from the fully engaged state to the fully released state) at a predetermined second time point ty, and the torque converter 18 is disengaged at a predetermined second time point ty. If the rotational speed difference ΔLU is predicted to be greater than or equal to the predetermined difference ΔLU_jdg [rpm], it is predicted that the shock occurring in the vehicle 10 will exceed the allowable range when the fuel recovery is performed at the predetermined second time point ty. . On the other hand, when it is predicted that the lockup clutch 18c is not released at the predetermined second time point ty, and when it is predicted that the rotational speed difference ΔLU of the torque converter 18 is less than the predetermined difference ΔLU_jdg at the predetermined second time point ty. , it is predicted that the shock occurring in the vehicle 10 when fuel recovery is performed at the predetermined second point in time ty is within the allowable range. For example, by applying the clutch oil pressure Plu predicted at a predetermined second time point ty to a map in which the relationship between the clutch oil pressure Plu and the operating state of the lockup clutch 18c is predetermined experimentally or by design. , at a predetermined second time point ty, it is determined whether or not the lockup clutch 18c is being released. For example, the clutch hydraulic pressure Plu predicted at the predetermined second time point ty is calculated based on the actual clutch hydraulic pressure Plu at the time of prediction and the decrease rate of the clutch hydraulic pressure Plu. The predetermined difference .DELTA.LU_jdg is a predetermined second point in time predetermined experimentally or by design for predicting whether or not the shock occurring in the vehicle 10 when fuel recovery is performed is within the allowable range. This is the determination value of the rotational speed difference ΔLU of the torque converter 18 at ty.

The decrease determining unit 90c determines that the engine rotation speed decrease amount ΔNe in the predetermined period T after the execution timing is set by the setting unit 90b is equal to or greater than the predetermined decrease amount ΔNe_jdg, and the fuel recovery is completed at the predetermined second time point ty. When the shock prediction unit 90d predicts that the shock that will occur in the vehicle 10 is within the allowable range when executed, the correction unit 90e adjusts the shock from the predetermined first time point tx set by the setting unit 90b to a predetermined number of times. The execution timing is corrected (reset) at time 2 ty. For example, the predetermined second time point ty is calculated based on a map in which the relationship between the engine rotation speed reduction amount ΔNe and the predetermined second time point ty is predetermined experimentally or by design. In this map, the larger the engine rotation speed reduction amount ΔNe, the earlier the predetermined second time point ty.

The return execution unit 90f determines whether or not the execution timing set by either the setting unit 90b or the correction unit 90e has come. When it is determined that the execution timing set by either the setting section 90b or the correction section 90e has come, the return execution section 90f executes fuel recovery, that is, restarts fuel supply to the engine 12. FIG.

FIG. 2 is an example of a flow chart for explaining the control operation of the electronic control unit 90 shown in FIG. The flowchart of FIG. 2 is repeatedly executed at predetermined time intervals, for example, when the vehicle 10 is running a fuel cut.

First, in step S10 corresponding to the function of the return determining section 90a, it is determined whether or not fuel recovery is to be executed. If the determination in step S10 is affirmative, step S20 is executed. If the decision in step S10 is negative, the process returns.

In step S20 corresponding to the function of the setting section 90b, the start time and end time of the release control of the lockup clutch 18c are set, and the execution timing of the fuel recovery is set at a predetermined first time point tx. Then step S30 is executed.

In step S30 corresponding to the function of the return execution section 90f, release control of the lockup clutch 18c is started. Then step S40 is executed.

In step S40 corresponding to the function of the decrease determination unit 90c, it is determined whether or not the engine rotation speed decrease amount ΔNe in the predetermined period T is equal to or greater than a predetermined decrease amount ΔNe_jdg. If the determination in step S40 is affirmative, step S50 is executed. If the determination in step S40 is negative, step S90 is executed.

At step S50 corresponding to the function of the shock prediction section 90d, a predetermined second time point ty is set at which it is predicted whether or not the shock occurring in the vehicle 10 is within the allowable range at step S60, which will be described later. Then step S60 is executed.

In step S60 corresponding to the function of the shock prediction section 90d, it is predicted whether or not the shock that will occur in the vehicle 10 when the fuel recovery is performed at the predetermined second time point ty is within the allowable range. If the determination in step S60 is affirmative, step S80 is executed. If the determination in step S60 is negative, step S70 is executed.

In step S70 corresponding to the function of the shock prediction section 90d, the predetermined second time ty is changed to a time earlier by a predetermined time tstep. The predetermined time tstep is a predetermined time for resetting the predetermined second time ty at which it is predicted whether or not the shock occurring in the vehicle 10 is within the allowable range. Shorter than the period between the time when it is determined whether or not the engine rotation speed decrease amount ΔNe is equal to or greater than the predetermined decrease amount ΔNe_jdg and the end time of the release control of the lockup clutch 18c set in step S20 It's time. Then step S50 is executed again.

In step S80 corresponding to the function of the correction unit 90e, the execution timing is corrected from the predetermined first time point tx set in step S20 to the predetermined second time point ty. Then step S90 is executed.

In step S90 corresponding to the function of the return execution section 90f, it is determined whether or not the execution timing set in either step S20 or step S80 has come. If the determination in step S90 is affirmative, step S100 is executed. If the determination in step S90 is negative, step S90 is executed again.

In step S100 corresponding to the function of the return execution section 90f, fuel recovery is executed, that is, fuel supply to the engine 12 is restarted. and return.

FIG. 3 is an example of a time chart when the flowchart of FIG. 2 is executed. The horizontal axis in FIG. 3 is time t [ms]. With respect to the engine rotation speed Ne and the fuel supply stop signal shown in FIG. 3, the solid line indicates the case of this embodiment in which the judgment in step S40 of the flow chart of FIG. A comparative example in which the execution timing is maintained at the predetermined first time point tx even though the determination in step S40 is affirmative is indicated by a one-dot chain line.

Before time t1, the fuel supply stop signal is turned on during coasting, the fuel is cut, and the lockup clutch 18c is in the fully engaged state.

At time t1, the engine rotation speed Ne becomes less than a predetermined rotation speed value Ne_jdg, and it is decided to execute fuel recovery.

At time t1, the lockup clutch 18c is released from the semi-engaged state to the fully released state from time t3 (that is, the control for decreasing the clutch oil pressure Plu). is determined to control the clutch oil pressure Plu so that the release control of is completed. Also, at time t1, the execution timing of the fuel recovery is set to time t7 when the release control of the lockup clutch 18c is completed. It should be noted that the time t7, which is the execution timing of the fuel recovery at the time t1, corresponds to the "predetermined first time point" in the present invention.

At time t4, it is determined that the engine rotation speed decrease amount ΔNe during the period from time t2 (>t1) to time t4 (t7>t4>t2), that is, the predetermined period T, is greater than or equal to the predetermined decrease amount ΔNe_jdg. It is expected that the shock produced by vehicle 10 will be acceptable if recovery is performed at time t5 (<t7). As a result, at time t4, the execution timing of fuel recovery is changed from time t7 to time t5 (that is, the time at which the fuel supply stop signal is switched from ON to OFF is changed from time t7 to time t5). Note that the time t5, which is changed from the time t4 as the fuel recovery execution timing, corresponds to the "predetermined second time point" in the present invention.

At time t5, the fuel supply stop signal is switched from ON to OFF, fuel recovery is executed, and at time t6 (>t5), the engine rotation speed Ne starts increasing and approaches the turbine rotation speed Nt. To go. As described above, in this embodiment, as compared with the comparative example, the engine stall resistance is improved by suppressing the decrease in the engine rotation speed Ne after the time t5.

According to the electronic control unit 90 of the present embodiment, (a) the setting unit 90b presets the fuel recovery execution timing to the predetermined first time point tx, and (b) the predetermined timing after setting the execution timing by the setting unit 90b. When it is determined that the engine rotation speed decrease amount ΔNe in the period T is equal to or greater than the predetermined decrease amount ΔNe_jdg, and fuel recovery is performed at a predetermined second time point ty earlier than the predetermined first time point tx, the vehicle 10 and a correction unit 90e for correcting the execution timing to a predetermined second time point ty when the shock occurring at is predicted to be within the allowable range. When the engine rotation speed decrease amount ΔNe is equal to or greater than the predetermined decrease amount ΔNe_jdg, that is, in a situation where there is a risk of engine stall due to a specific condition, the fuel recovery execution timing is earlier than in other situations (=predetermined is corrected at the second time ty), the engine stall resistance is improved. When the engine rotation speed decrease amount ΔNe is less than the predetermined decrease amount ΔNe_jdg, that is, in a situation where there is no risk of engine stall occurring, the time point at which the fuel recovery execution timing is later (=predetermined first tx), a decrease in fuel consumption is suppressed. Therefore, the deterioration of fuel efficiency is suppressed while the engine stall resistance is improved. In this way, fuel recovery is executed at the predetermined second time point ty at which the shock occurring in the vehicle 10 is predicted to be within the allowable range. is suppressed.

According to the electronic control unit 90 of the present embodiment, when it is predicted that the lockup clutch 18c is disengaged at the predetermined second time point ty and the rotational speed difference ΔLU of the torque converter 18 is equal to or greater than the predetermined difference ΔLU_jdg, It is predicted that the shock occurring in the vehicle 10 will exceed the allowable range when fuel recovery is performed at the predetermined second time ty. Thus, when it is predicted that the lockup clutch 18c is disengaging and the rotation speed difference ΔLU of the torque converter 18 is greater than or equal to the predetermined difference ΔLU_jdg, it is predicted that the shock occurring in the vehicle 10 will exceed the allowable range. Thus, the fuel recovery execution timing corrected by the correction unit 90e is set to the timing at which the occurrence of the shock in the vehicle 10 is suppressed.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other aspects.

Although the vehicle 10 is an FR vehicle in the above embodiment, it is not limited to this. For example, the vehicle 10 may be a FF (front engine/front drive) vehicle.

In the above-described embodiment, when the shock prediction unit 90d predicts that the shock occurring in the vehicle 10 is within the allowable range when the fuel recovery is performed at the predetermined second time point ty, the correction unit 90e Although the execution timing is corrected from the first time point tx to the predetermined second time point ty, the present invention is not limited to this mode. For example, when the engine rotation speed decrease amount ΔNe is equal to or greater than a predetermined decrease amount ΔNe_jdg by the decrease determination unit 90c, the shock prediction unit 90d predicts whether or not the shock occurring in the vehicle 10 is within the allowable range. Alternatively, the correction unit 90e may correct the execution timing from the predetermined first time point tx to the predetermined second time point ty.

It should be noted that what has been described above is merely an embodiment of the present invention, and the present invention can be implemented in a mode with various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the invention.

10: Vehicle 12: Engine 18: Torque Converter 18c: Lockup Clutch 32: Drive Wheel 90: Electronic Control Device (Control Device)
90b: Setting unit 90e: Correction unit Ne: Engine rotation speed (engine rotation speed)
T: Predetermined period of time tx: Predetermined first time point ty: Predetermined second time point ΔNe: Engine rotation speed decrease amount (decrease amount)
ΔNe_jdg: Predetermined decrease amount (predetermined amount)

Claims (1)

Applied to a vehicle equipped with an engine and a torque converter provided between the engine and drive wheels and having a lock-up clutch, there is a possibility that the engine stalls when the fuel of the engine is cut. When it is determined that there is a lockup clutch, the vehicle control device executes fuel recovery after starting release control to put the lockup clutch in a completely released state,
a setting unit that presets the execution timing of the fuel recovery to a predetermined first point in time;
If it is determined that the amount of decrease in the rotation speed of the engine during the predetermined period after the setting of the execution timing by the setting unit is equal to or greater than a predetermined amount, the execution timing is set to a predetermined time earlier than the predetermined first time point. and a correction unit that corrects at two points in time.

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