JP6783021B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device used in a vehicle that employs idling stop (IDS) control.

In recent years, idling stop control has been widely adopted in vehicles whose drive source is an engine. Idling stop control is a technology for improving fuel efficiency by stopping unnecessary idling rotation of the engine (idling stop).

In the idling stop control, for example, when the driver operates the brake and the vehicle speed drops below a predetermined idling stop implementation vehicle speed due to the operation of the brake, the engine is automatically stopped. If the driver's braking operation is released during idling stop, the engine will automatically restart.

Japanese Unexamined Patent Publication No. 2015-117738

Recently, in order to secure a long idling stop time, the control of setting the vehicle speed for performing idling stop to a value larger than 0 km / h and stopping the engine during deceleration running of the vehicle has become mainstream.

However, under that control, even though the vehicle was decelerating smoothly with a constant braking force, when the engine was stopped (idling stop was implemented), the driving force was released and the vehicle suddenly decelerated. As it becomes larger, the brake feeling deteriorates.

An object of the present invention is to provide a vehicle control device capable of reducing a change in deceleration of a vehicle due to the implementation of idling stop while the vehicle is running.

In order to achieve the above object, the vehicle control device according to the present invention is for transmitting / shutting off the power between the engine, the transmission for shifting the power transmitted from the engine to the wheels, and the engine and the wheels. A control device used for a vehicle equipped with a hydraulic friction engaging element that is engaged / disengaged, and includes a plurality of idling conditions including a vehicle speed condition in which the vehicle speed is lower than the vehicle speed at which the idling stop system is implemented, which is larger than 0 km / h. An idling stop implementing means for stopping the engine when the stop condition is satisfied, and a flood control supplied to the friction engaging element after the idling stop condition other than the vehicle speed condition is satisfied and before the vehicle speed condition is satisfied. Including a hydraulic pressure reducing means for reducing.

According to this configuration, the engine is stopped when a plurality of idling stop conditions are satisfied. One of the plurality of idling stop conditions includes a vehicle speed condition in which the vehicle speed is lowered to the idling stop implementation vehicle speed or less, which is larger than 0 km / h. Therefore, if the vehicle speed condition is satisfied after the idling stop condition other than the vehicle speed condition is satisfied, the engine is stopped while the vehicle is traveling (during deceleration). Since the idling rotation of the engine is eliminated while the vehicle is running, fuel efficiency can be improved as compared with the control in which the engine is stopped after the vehicle is stopped.

Further, in that case, a hydraulic type that is engaged / released in order to transmit / shut off power between the engine and the wheels after the idling stop condition other than the vehicle speed condition is satisfied and before the vehicle speed condition is satisfied. The oil supply to the friction engagement element is reduced. As a result, the transmitted torque capacity of the friction engaging element is reduced, so that when the engine is stopped in response to the establishment of the vehicle speed condition, it is possible to suppress the reduction change of the engine torque due to the stop of the engine being transmitted to the wheels. As a result, it is possible to reduce the change in deceleration of the vehicle due to the implementation of idling stop while the vehicle is running.

According to the present invention, since the engine is stopped while the vehicle is running, the fuel efficiency can be improved as compared with the control in which the engine is stopped after the vehicle is stopped. The change in deceleration can be reduced.

It is a figure which shows the structure of the main part of the vehicle which mounted the control device which concerns on one Embodiment of this invention. It is a skeleton diagram which shows the structure of the drive system of a vehicle. It is a figure which shows the state of each engaging element in P range, R range, N range and D range. It is a flowchart which shows the flow of the clutch pressure reduction processing which is executed before the engine is stopped by idling stop control. It is a figure which shows the time change of the acceleration, the vehicle speed, the engine speed, the clutch pressure and the engine torque of a vehicle before and after the engine stop by the idling stop control.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main part composition of the vehicle>
FIG. 1 is a diagram showing a configuration of a main part of a vehicle 1 equipped with a control device according to an embodiment of the present invention.

The vehicle 1 is an automobile whose drive source is the engine 2.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into intake air, an ignition plug for generating an electric discharge in the combustion chamber, and the like. Has been done. Further, the engine 2 is provided with a starter for starting the engine 2.

The power plant including the engine 2 includes a torque converter 3, a stepped automatic transmission (AT) 4, and a differential gear 5 (see FIG. 2).

Further, the vehicle 1 is equipped with an ECU (Electronic Control Unit) having a configuration including a microcomputer. The microcomputer has, for example, a CPU, ROM and RAM, a data flash (flash memory), and the like. In order to control each part of the vehicle 1, the vehicle 1 is equipped with a plurality of ECUs, and each ECU is connected so as to enable bidirectional communication by a CAN (Controller Area Network) communication protocol. The plurality of ECUs include an engine ECU 6 for engine control, an ATEC U7 for shift control, a brake ECU 8 for brake control, and an IDSE ECU 9 for idling stop (IDS) control. Various sensors necessary for control are connected to the engine ECU 6, ATECU 7, brake ECU 8 and IDSE ECU 9.

The engine ECU 6 has an electronic throttle valve, an injector, and an ignition for starting, stopping, and adjusting the output of the engine 2 based on the information acquired from the detection signals of various sensors and / or various information input from other ECUs. Control plugs and starters.

Since the ATECU 7 changes the range or the shift stage of the automatic transmission 4 based on the information acquired from the detection signals of various sensors and / or various information input from other ECUs, each part of the automatic transmission 4 Controls the valves included in the hydraulic circuit for supplying oil to the engine. The valve includes a C2 solenoid valve 11 for controlling the hydraulic pressure supplied to the clutch C2 (see FIG. 2). As the C2 solenoid valve 11, a valve capable of controlling the output oil pressure by a current value, for example, a normally open type linear solenoid valve is used.

The sensor connected to the brake ECU 8 includes a brake sensor 12, a vehicle speed sensor 13, and the like.

The brake sensor 12 outputs a detection signal according to the amount of operation of the brake pedal arranged in the vehicle interior.

The vehicle speed sensor 13 includes, for example, a rotor made of a magnetic material that rotates as the vehicle 1 travels, and an electromagnetic pickup provided in non-contact with the rotor. Every time the rotor rotates by a certain angle, a pulse signal is output as a detection signal from the electromagnetic pickup. Since the frequency of the pulse signal corresponds to the vehicle speed, the brake ECU 8 converts the frequency of the pulse signal input from the vehicle speed sensor 13 into the vehicle speed.

The brake ECU 8 controls the brake actuator 14 and the like based on information acquired from detection signals of various sensors (operation amount of the brake pedal, vehicle speed of the vehicle 1) and / or various information input from other ECUs. , The braking force applied to the wheels by each brake is controlled so that the vehicle 1 is braked while the posture of the vehicle 1 is kept stable.

Information such as the vehicle speed and the operation amount of the brake pedal is input from the brake ECU 8 to the IDSECU 9 as information necessary for idling stop control.

In the idling stop control, when the driver performs a braking operation (for example, stepping on the brake pedal) while the vehicle 1 is running, the IDSECU 9 repeatedly determines whether or not the idling stop condition (IDS condition) is satisfied. Judged. The idling stop condition includes, for example, a braking condition that the braking operation is continued for a certain period of time or longer, a steering torque condition that the steering torque applied to the steering mechanism (steering wheel) of the vehicle 1 is less than the IDS prohibited torque, and the like. The battery condition that the SOC (State Of Charge) of the battery mounted on the vehicle 1 is equal to or higher than a predetermined value, the vehicle speed condition that the vehicle speed is greater than 0 km / h and the vehicle speed at which the idling stop is implemented (for example, 10 km / h) or less, etc. Is included. When all the idling stop conditions are satisfied, the IDSE ECU 9 outputs an idling stop request to the engine ECU 6, and the engine ECU 6 stops the engine 2.

While the engine 2 is stopped by the idling stop control, it is repeatedly determined whether or not the predetermined return condition is satisfied. The return condition includes, for example, a condition that the brake operation by the driver is released. When the return condition is satisfied, the IDSEC U9 outputs a restart request to the engine ECU 6. In response to this restart request, the engine ECU 6 restarts the engine 2.

<Driving system configuration>
FIG. 2 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. The output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is rotatably provided about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

When the E / G output shaft is rotated while the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 to the turbine runner 32 is generated. This flow of oil is received by the turbine runner 32, and the turbine runner 32 rotates. At this time, the amplification action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft.

In the state where the lockup clutch 33 is engaged, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 31 and the turbine runner 32 are integrally rotated.

The automatic transmission 4 is a 4-speed AT having four forward speeds and one reverse speed. The automatic transmission 4 includes an input shaft 41, an output shaft 42, a center shaft 43, and a labinyo-type planetary gear mechanism 44.

The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and is provided so as to be integrally rotatable around the same rotation axis as the turbine runner 32.

The output shaft 42 is provided parallel to the input shaft 41.

The center shaft 43 is provided on the same rotation axis as the input shaft 41, separated from the input shaft 41 on the side opposite to the engine 2 side.

The planetary gear mechanism 44 includes a front sun gear 51, a rear sun gear 52, a carrier 53, a ring gear 54, a long pinion gear 55, and a short pinion gear 56. The front sun gear 51 is fitted on the center shaft 43 so as to be relatively rotatable. The rear sun gear 52 is provided on the side opposite to the engine 2 side with respect to the front sun gear 51, and is externally fitted to the center shaft 43 so as to be relatively rotatable. A center shaft 43 is connected to the carrier 53, and the carrier 53 is provided so as to be rotatable integrally with the center shaft 43. The carrier 53 rotatably supports the long pinion gear 55 and the short pinion gear 56. The ring gear 54 has an annular shape surrounding the carrier 53 on the outer side in the rotational radial direction of the rear sun gear 52, and meshes with the long pinion gear 55. The long pinion gear 55 has a shaft length longer than the shaft length of the short pinion gear 56, and meshes with the front sun gear 51. The short pinion gear 56 meshes with the rear sun gear 52 and the long pinion gear 55.

The ring gear 54 holds the first output gear 45 so as to have a common rotation axis. The first output gear 45 is meshed with a second output gear 46 that is supported by the output shaft 42 so as not to rotate relative to each other. Further, a third output gear 63 is supported on the output shaft 42 so as not to rotate relative to each other, and the third output gear 63 meshes with a ring gear provided in the differential gear 5. As a result, the rotation of the ring gear 54 is transmitted to the differential gear 5 via the first output gear 45, the second output gear 46, the output shaft 42, and the third output gear 63. Then, the rotation is transmitted to the wheels of the vehicle 1 (for example, the left and right front wheels) via the drive shaft extending from the differential gear 5 to the left and right.

Further, the automatic transmission 4 includes three clutches C1 to C3, two brakes B1 and B2, and a one-way clutch F.

The clutch C1 is switched between an engaged state (on) in which the input shaft 41 and the front sun gear 51 are connected and an released state (off) in which the connection is released.

The clutch C2 is switched between an engaged state (on) in which the input shaft 41 and the rear sun gear 52 are connected and an released state (off) in which the connection is released.

The clutch C3 is switched between an engaged state (on) in which the input shaft 41 and the center shaft 43 (carrier 53) are connected and an released state (off) in which the connection is released.

The brake B1 is switched between an engaged state (on) for braking the front sun gear 51 and an released state (off) for allowing the front sun gear 51 to rotate.

The brake B2 is switched between an engaged state (on) for braking the carrier 53 and an released state (off) for allowing the carrier 53 to rotate.

The one-way clutch F allows only normal rotation of the carrier 53 (rotation in the same direction as the output shaft of the engine 2).

<Engagement table>
FIG. 3 is a diagram showing states of clutches C1 to C3, brakes B1 and B2, and one-way clutch F in the P range, R range, N range, and D range.

In FIG. 3, “◯” indicates that the clutches C1 to C3, the brakes B1 and B2, and the one-way clutch F are in an engaged state.

In the P range and N range, the clutches C1 to C3 and the brakes B1 and B2 are released.

In the R range, the clutch C1 and the brake B2 are engaged, and the clutches C2 and C3 and the brake B1 are released.

In the first speed of the D range, the clutch C2 and the one-way clutch F are engaged, and the clutches C1 and C3 and the brakes B1 and B2 are released.

In the second speed stage of the D range, the clutch C2 and the brake B1 are engaged, and the clutches C1 and C3 and the brake B2 are released.

In the 3rd speed stage of the D range, the clutches C2 and C3 are engaged, and the clutch C1 and the brakes B1 and B2 are released.

In the 4th speed stage of the D range, the clutch C3 and the brake B1 are engaged, and the clutches C1 and C2 and the brake B2 are released.

<Clutch pressure reduction processing>
FIG. 4 is a flowchart showing the flow of the clutch pressure reduction process executed before the engine 2 is stopped by the idling stop control. Further, FIG. 5 is a diagram showing changes in the acceleration, vehicle speed, engine speed, hydraulic pressure (clutch pressure) of the clutch C2 and engine torque of the vehicle 1 before and after the engine 2 is stopped by idling stop control.

For example, while the vehicle 1 is running, the clutch pressure reduction process shown in FIG. 4 is executed by the ATECU 7 before the engine 2 is stopped by the idling stop control.

In the clutch pressure reduction process, it is determined whether or not all the idling stop conditions (IDS conditions) other than the vehicle speed condition are satisfied (step S1).

While all the idling stop conditions other than the vehicle speed condition are not satisfied (NO in step S1), the hydraulic pressure (clutch pressure) supplied to the clutch C2 is held by the normal hydraulic pressure required to maintain the engaged state. As such, the current supplied to the C2 solenoid valve 11 is controlled (step S2).

When all the idling stop conditions other than the vehicle speed condition are satisfied (YES in step S1), the vehicle speed is equal to or higher than the idling stop implementation vehicle speed and the predetermined value α (for example, α = 1 to 2 km / h) is added to the idling stop implementation vehicle speed. It is determined whether or not the oil pressure has dropped within the following hydraulic pressure reduction range (step S3).

While the vehicle speed is higher than the oil pressure reduction range (NO in step S3), the current supplied to the C2 solenoid valve 11 is controlled so that the clutch pressure is maintained at the normal oil pressure (step S2).

When the vehicle speed drops within the oil pressure reduction range (YES in step S3), the clutch pressure decreases at a speed of change according to the deceleration of the vehicle 1, that is, the greater the deceleration of the vehicle 1, the more rapidly the clutch pressure decreases. The current supplied to the C2 solenoid valve 11 is controlled so as to be performed (step S4, time T1 in FIG. 5).

After the clutch pressure is reduced, it is determined whether or not all the idling stop conditions including the vehicle speed condition are satisfied (step S5).

When all the idling stop conditions including the vehicle speed condition are not satisfied (NO in step S5), it is determined whether or not all the idling stop conditions other than the vehicle speed condition are satisfied (step S1). Then, when all the idling stop conditions other than the vehicle speed condition are not satisfied (NO in step S1), or when the vehicle speed rises to a vehicle speed higher than the oil pressure reduction range (NO in step S2), the clutch pressure. The current supplied to the C2 solenoid valve 11 is controlled so that the pressure rises to the normal oil pressure (step S2). On the other hand, if all the idling stop conditions other than the vehicle speed condition are satisfied (YES in step S1), or if the vehicle speed is within the oil pressure reduction range (YES in step S2), the clutch pressure is reduced or the reduced oil pressure. The current supplied to the C2 solenoid valve 11 is controlled so as to be held in (step S4).

When all the idling stop conditions including the vehicle speed condition are satisfied after the clutch pressure is reduced (YES in step S5), the clutch pressure reduction process is completed. Further, when all the idling stop conditions including the vehicle speed condition are satisfied, the IDSE ECU 9 outputs an idling stop request to the engine ECU 6, and the engine ECU 6 stops the engine 2 (time T2 in FIG. 5).

<Effect>
As described above, one of the idling stop conditions includes a vehicle speed condition in which the vehicle speed is lowered to the idling stop implementation vehicle speed or less, which is larger than 0 km / h. Therefore, if the vehicle speed condition is satisfied after all the idling stop conditions other than the vehicle speed condition are satisfied, the engine 2 is stopped while the vehicle 1 is traveling (during deceleration). Since the idling rotation of the engine 2 is eliminated while the vehicle 1 is running, the fuel efficiency can be improved as compared with the control in which the engine 2 is stopped after the vehicle 1 is stopped.

When the vehicle 1 is traveling at a creep vehicle speed or lower, the engine torque is transmitted to the wheels (driving wheels). While the vehicle 1 is running in this driving state, when the engine 2 is stopped with the clutch C2 and the like constituting the shift stage at that time completely engaged, as shown by a virtual line in FIG. A sudden reduction change in engine torque is transmitted to the wheels (driving wheels), and the reduction change in engine torque appears as a reduction change in acceleration of the vehicle 1.

Therefore, when the engine 2 is stopped while the vehicle 1 is running, it is supplied to the clutch C2 after the idling stop conditions other than the vehicle speed condition are satisfied and before all the idling stop conditions including the vehicle speed condition are satisfied. The existing hydraulic pressure (clutch pressure) is reduced. As a result, the transmission torque capacity of the clutch C2 is reduced, so that when the engine 2 is stopped in response to the establishment of the vehicle speed condition, it is possible to suppress the reduction change of the engine torque due to the stop of the engine 2 being transmitted to the wheels. As a result, it is possible to reduce the change in the deceleration of the vehicle 1 due to the implementation of the idling stop while the vehicle 1 is running.

Further, the clutch pressure is reduced at a changing speed according to the deceleration of the vehicle 1. That is, the larger the deceleration of the vehicle 1, the more rapidly the clutch pressure is reduced, and the smaller the deceleration of the vehicle 1, the gradual reduction of the clutch pressure. As a result, the clutch pressure can be reduced before the engine 2 is stopped regardless of the deceleration of the vehicle 1, and the change in the deceleration of the vehicle 1 due to the implementation of the idling stop while the vehicle 1 is running is reduced. it can.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, in the above-described embodiment, the hydraulic pressure supplied to the clutch C2 decelerates the vehicle 1 after the idling stop conditions other than the vehicle speed condition are satisfied and before all the idling stop conditions including the vehicle speed condition are satisfied. It is said that it will be reduced at a rate of change according to. However, the oil pressure supplied to the clutch C2 may be reduced at a constant rate of change regardless of the deceleration of the vehicle 1.

Further, some or all of the functions of the engine ECU 6, the ATECU 7, the brake ECU 8 and the IDS ECU 9 may be integrated into one ECU.

Further, although the configuration in which the stepped automatic transmission 4 is mounted on the vehicle 1 is taken up, the present invention is a continuously variable transmission or a power split type equipped with a clutch that is held in an engaged state when the vehicle 1 is running. It can also be applied to vehicles equipped with a continuously variable transmission. The power split type continuously variable transmission is provided with a belt-type continuously variable transmission mechanism that shifts power steplessly by changing the gear ratio and a constant transmission mechanism that shifts power at a constant gear ratio, and power of a drive source. Is a transmission that can be transmitted by dividing it into two systems.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Vehicle 2: Engine 4: Automatic transmission (transmission)
6: Engine ECU (control device, idling stop implementation means)
7: ATECU (control device, oil pressure reducing means)
9: IDSECU (control device, idling stop implementation means)
C2: Clutch (friction engagement element)

Claims (1)

Equipped with an engine, a transmission that shifts the power transmitted from the engine to the wheels, and a hydraulic friction engagement element that engages / disengages to transmit / disconnect power between the engine and the wheels. It is a control device used for the vehicle
Idling stop implementation means in which the engine is stopped in response to the satisfaction of a plurality of idling stop conditions including a vehicle speed condition that the vehicle speed has dropped below the vehicle speed of 0 km / h.
After the idling stop condition other than the vehicle speed condition is satisfied and before the vehicle speed condition is satisfied, the hydraulic pressure supplied to the friction engaging element is applied in the driving state in which the engine torque of the engine is transmitted to the wheels. A vehicle control device, including a hydraulic pressure reducing means for reducing.

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