JP2001082594A - Vehicle control device - Google Patents

Abstract

(57) Abstract: In a vehicle control device, the durability of a belt-type continuously variable transmission and the response are improved by preventing slippage between a belt and a pulley in a belt-type continuously variable transmission when an engine is started. SOLUTION: When a restart condition of an engine 11 is satisfied, E
When the NG-ECU 62 restarts the engine 11, the CV
The T-ECU 61 executes the ND shift control, that is, the power transmission of the hydraulic friction element (clutch), after the line pressure PL of the belt-type continuously variable transmission 14 is secured to a predetermined value or more by driving the oil pump. And ENG-ECU 62
The engine 11 is forcibly maintained in an idle state and the required line pressure is maintained at a low level until the ND shift control ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle having a belt-type continuously variable transmission, which can automatically restart an engine.

[0002]

2. Description of the Related Art As a method of reducing exhaust gas and improving fuel efficiency,
There have been proposed various technologies for automatically stopping an engine when a vehicle is stopped in an idle state at a traffic light and automatically restarting the vehicle when the vehicle starts to smoothly start the vehicle. In this case, it takes a long time to restart the engine, which may worsen the fuel efficiency, and it is important how to restart the engine quickly and smoothly.

[0003] Incidentally, a vehicle equipped with a manual transmission mechanism (M
T), the engine is automatically stopped when stop conditions such as the vehicle is stopped and the shift lever is in the neutral position, and the clutch pedal is operated to shift the shift lever to the traveling position. When depressed, this is detected, the engine is automatically restarted, and the start of the engine is realized by transmitting the rotation of the engine to the manual transmission mechanism while returning the clutch pedal with the completion of the shift lever shift. ing.

[0004]

SUMMARY OF THE INVENTION From such a viewpoint,
There is a demand to apply the idle stop control described above to an automatic transmission, particularly to a belt-type continuously variable transmission. However, when the above-described idle stop control is applied to the belt-type continuously variable transmission, the following problem occurs. That is, since the AT vehicle equipped with the belt-type continuously variable transmission does not have the clutch pedal, the restart command is received when the shift lever is shifted to the traveling position.

In addition, the belt type continuously variable transmission usually has a hydraulic friction element whose connection to and disconnection from the engine is controlled by hydraulic pressure, and only when a predetermined hydraulic pressure is generated. Are engaged to transmit the rotational force from the engine. In addition, the belt-type continuously variable transmission wraps a belt between a primary pulley connected to the input shaft and a secondary pulley connected to the output shaft,
By supplying and discharging the hydraulic pressure to and from the cylinder of each pulley, each groove width of the primary pulley and the secondary pulley is relatively changed to shift the speed, and each pulley and the belt only when a predetermined hydraulic pressure is generated. Are driven without slipping and transmit torque from the engine.

However, the oil pressure used for controlling the belt-type continuously variable transmission is obtained from an oil pump directly connected to the output shaft of the engine. in this case,
Since the hydraulic pressure required for each pulley to hold the belt is greater than the hydraulic pressure required to engage the hydraulic friction element,
When the engine is restarted after detecting the operation of the shift lever from the neutral position to the traveling position, the oil pump operates and the hydraulic pressure increases, but the hydraulic pressure required to engage the low-pressure hydraulic friction element After the securing, the hydraulic pressure required to hold the belt on each pulley cylinder is secured. Then, before the hydraulic pressure capable of sufficiently holding the belt is supplied to the pulley cylinder, the hydraulic friction element is engaged and the pulley is driven to rotate, so that a slip occurs between the pulley and the belt, causing damage. There is a possibility that it will end up. Further, since the holding force of the belt is proportional to the input torque, when there is a high input, it takes time for the oil pressure of the oil pump to rise to the oil pressure required for the holding force of the belt, and the response is deteriorated.

The present invention has been made to solve such a problem, and it is intended to improve the durability and the response by preventing the belt and the pulley of the belt type continuously variable transmission from slipping at the time of engine start. It is an object of the present invention to provide an intended vehicle control device.

[0008]

In order to achieve the above object, in the vehicle control device according to the first aspect of the present invention, the hydraulic pressure released when the shift lever is engaged when the shift lever is in the traveling position and is released when the shift lever is in the neutral position. In a belt-type continuously variable transmission including a friction element, when the shift lever is switched from the neutral position to the traveling position and the engine is started by the engine starting means,
The hydraulic pressure determining means determines whether or not the hydraulic pressure supplied to the control hydraulic device of the belt-type continuously variable transmission is a predetermined value. The start of engagement of the hydraulic friction engagement element is commanded.

Therefore, after the supply hydraulic pressure to the control hydraulic device of the belt-type continuously variable transmission reaches a predetermined value, that is, by securing the hydraulic pressure necessary for the pulley to hold the belt, the rotational force of the pulley is increased. Can be transmitted to the belt, the engagement of the hydraulic friction engagement element is started, and the rotational force from the engine is transmitted to the belt-type continuously variable transmission.
Damage due to slippage between the pulley and the belt is prevented, and durability is improved.

In the vehicle control device according to the second aspect of the present invention, an output increase inhibiting means for inhibiting an increase in the output of the engine during the engagement control of the hydraulic friction engagement element is provided. Therefore, even if there is a high input, the engine output does not increase until the engagement of the hydraulic friction engagement element is completed, and the target line pressure also decreases, so the hydraulic pressure required for the belt holding force also decreases. The response is improved by shortening the time until the hydraulic pressure is secured.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration of a vehicle control device according to an embodiment of the present invention, FIG. 2 is a schematic configuration of a belt-type continuously variable transmission, and FIG. 3 is a flowchart of engine restart control by the vehicle control device. Show.

In the vehicle control apparatus according to the present embodiment, as shown in FIG.
The power is transmitted to a belt-type continuously variable transmission (CVT) 14 via a torque converter 12 and a forward / reverse switching mechanism 13, and is transmitted from the belt-type continuously variable transmission 14 to left and right drive wheels via a front differential (not shown). It's getting upset. The forward / reverse switching mechanism 13 outputs the rotational direction of the rotation input from the engine 11 via the torque converter 12 to the belt-type continuously variable transmission 14 as forward rotation or reverse rotation, and outputs the rotational friction. It has a forward clutch, a reverse brake, a planetary gear mechanism, and the like (not shown) as elements.

For example, the forward clutch is engaged in a state where a predetermined oil pressure is applied and transmits the rotational force from the engine 11 as a forward rotation, and is disengaged when the predetermined oil pressure is not applied. This serves to cut off (prevent) transmission of rotational force from the engine 11. As shown in FIG. 2, the belt-type continuously variable transmission mechanism 14 includes a primary pulley 21 connected to the output side of the engine 11, a secondary pulley 31 connected to the noise shaft of the vehicle, and both pulleys 21, 31. Belt 41 stretched between
The rotation input from the forward / reverse switching mechanism 13 to the primary shaft 22 is input from the coaxially integrated primary pulley 21 to the secondary pulley 31 via the belt 41 and output to the secondary shaft 32. It has become.

That is, the primary pulley 21 has a fixed sheave 23 and a movable sheave 24, and a primary cylinder 21a is formed on the back side of the movable sheave 24. Therefore, by supplying and discharging hydraulic pressure to and from the primary cylinder 21a, the movable sheave 24 moves relative to the fixed sheave 23,
The groove width of the pulley can be made variable. On the other hand, similarly, the secondary pulley 31 has a fixed sheave 33 and a movable sheave 34, and a secondary cylinder 31a is formed on the back side of the movable sheave 34. Therefore, by supplying and discharging the hydraulic pressure to and from the secondary cylinder 31a, the movable sheave 34 can be moved relative to the fixed sheave 33, and the groove width of the pulley can be made variable.

The belt-type continuously variable transmission mechanism 14 includes:
As shown in FIGS. 1 and 2, the control is performed by a hydraulic circuit 50. That is, the secondary cylinder 31
The secondary hydraulic pressure Ps (line pressure PL) adjusted by the regulator valve 51 serving as a pressure adjusting valve is applied to a. Pp is added. Reference numeral 53 denotes an oil pan, and 54 denotes an oil pump that supplies oil from the oil pan 53 to the regulator valve 51 side.

The electronic circuit unit (CVT-ECU) 61 for the belt-type continuously variable transmission mechanism includes the engine 1
1 electronic circuit unit (EN
G-ECU) 62 while communicating with the engine 1
1, the information on the operating state of the vehicle, the driving state of the vehicle, and the shift operation information (parking (P), reverse (R), neutral (N), traveling (D)) of the shift lever 63 operated by the driver, etc. Then, the drive of the hydraulic circuit 50 for the belt-type continuously variable transmission mechanism is controlled to control the speed ratio and the line pressure of the belt-type continuously variable transmission mechanism 14. Input signals to the CVT-ECU 61 include a primary rotational speed sensor, a secondary rotational speed sensor, a line pressure sensor, a primary pressure sensor, and the like.
The regulator valve 51 and the speed ratio control valve 52
Is controlled by an electromagnetic solenoid valve (not shown). Basically, the gear ratio is changed based on the vehicle speed and the throttle opening, and the line pressure is changed based on the CVT input torque and the gear ratio.

On the other hand, the ENG-ECU 62 includes detection signals such as an engine speed sensor, a throttle opening sensor, a vehicle speed sensor, a crank angle sensor (cam angle sensor), a water temperature sensor, an oil temperature sensor, and a brake switch, and a CVT-EC.
Information from U61 is input, and engine 11 is controlled.

In FIG. 1, a starter 64 is energized and driven by a battery 66 via an ignition switch 65 to rotate and start the engine 11. Here, the starter 64 is also energized and driven via a relay 67 selectively driven by the ENG-ECU 62 on condition that the ignition switch 65 is set to ON. The driving of the starter 64 via the relay 67 executes the restart of the engine 11 from an idle stop state described later, and the restart condition is managed by the CVT-ECU 61 and the ENG-ECU 62.

In this embodiment, when the shift lever 63 is switched from the neutral position (N) to the traveling position (D) (R) to start the engine 11 in this embodiment, the line pressure sensor CVT receiving the detection result
-The ECU 61 (oil pressure determining means) determines whether or not the line pressure PL to the hydraulic circuit 50 of the belt-type continuously variable transmission 14 is a predetermined value, that is, whether or not the pressure is a belt holding pressure, and the line pressure PL reaches the predetermined value. At this time, the start of engagement of the hydraulic friction engagement element is commanded, and an increase in the output of the engine 11 is prohibited during the engagement control of the hydraulic friction engagement element.

Here, the engine restart control by the vehicle control device of the present embodiment is performed by the CVT-ECU 61 and the ENG.
-The engine control and the speed change control respectively executed by the ECU 62 will be described in detail based on the flowchart of FIG.

As shown in FIG. 3, in step S1 of the ENG-ECU 62, it is determined whether or not the engine 11 has stopped while the vehicle is operating, based on whether or not the stop condition is satisfied. Here, the stop condition of the engine 11 is determined by whether the shift lever 63 is located at the neutral (N) position or not.
1 is higher than a predetermined temperature, the temperature of the hydraulic oil of the belt-type continuously variable transmission 14 is higher than a predetermined temperature, and the vehicle speed is 0 (stop) for more than a predetermined time. And a plurality of conditions such as whether the brake switch is in the ON state (whether the brake is operating), and when all of these conditions are satisfied, it is determined that the engine stop condition is satisfied. . Therefore, for example, the vehicle stops at an intersection or the like in a state where the vehicle is sufficiently warmed along with the traveling of the vehicle, and depresses a brake pedal,
Alternatively, when the shift lever 63 is set to neutral (N) while the parking brake is operated, it is determined that the engine is stopped.

If it is determined in step S1 that the engine 11 has stopped, the ENG-ECU 62 stops the engine 11 in step S2, and at the same time, the CVT in step S3.
-ENG-ECU 62 outputs an engine stop signal to ECU 61, and then, in step S4, ENG-ECU 62
It is in a state of waiting for the engine restart signal from the T-ECU 61. On the other hand, the CVT-ECU 61
In step 1, the engine waits for an input of an engine stop signal from the ENG-ECU 62. When the engine stop signal is input, the process proceeds to step T2, where it is determined whether the restart condition of the engine 11 is satisfied. The restart condition of the engine 11 is such that the shift lever 63 is shifted from the neutral (N) position to the traveling (D) position or the reverse (R) position, the vehicle speed is 0 (stop), or the brake switch is in the ON state. (When the brake is operating), and when all of these conditions are satisfied, it is determined that the restart condition of the engine 11 is satisfied.

If it is determined in step T2 that the condition for restarting the engine 11 is satisfied, then in step T3 the CVT
-ECU 61 outputs an engine restart signal to ENG-ECU 62, and at the same time, at step T4, sets line pressure PL in hydraulic circuit 50 of belt-type continuously variable transmission 14.
Control is started, and in step T5, the CVT-ECU 6
1 indicates that the ENG-ECU 62 restarts the engine 11 to drive the oil pump, and the line pressure PL
Is a predetermined value, that is, a standby state is reached until the pulling pressure of the pulleys 21 and 31 does not slip with the belt 41.
The securing of the line pressure PL in the hydraulic circuit 50 can be determined using a method of estimating using the detection value of the line pressure sensor, the oil temperature sensor, and the elapsed time from the start of the line pressure control. On the other hand, when the engine restart signal is input from the CVT-ECU 61 in step S4, the ENG-ECU 62 drives the starter 64 to start restarting the engine 11 in step S5.

The ENG-ECU 62 controls the engine 1
When the restart of the engine 1 is started, it is determined in a step S6 whether or not the start of the engine 11 is completed. The determination of the completion of the start is made, for example, by determining whether or not the engine 11 has started rotating at a predetermined rotational speed or more that exceeds the rotational speed provided by the starter 64. When the rotation of the engine 11 at a predetermined rotation speed or more is detected, the start of the starter 64 is stopped, and the CVT-ECU 61 is stopped in step S7.
, An ND control signal (shift operation permission signal) is output to the engine 11 at the same time, and the engine 11 is forcibly maintained in an idle state, that is, a low rotation speed state. Then, step S9
At this point, the system is in a state of waiting for an ND control end signal from the CVT-ECU 61.

On the other hand, as soon as the engine 11 is restarted and the oil pump is driven, the oil pressure rises immediately. CVT-EC
In U61, in step T5, it is determined whether or not the line pressure PL at which the pulleys 21 and 31 do not slip with the belt 41 is secured. If the line pressure has reached a predetermined value, the process proceeds to the next step. At step T6, the ENG-ECU
If the ND control signal has been input from step 62,
At 7, the ND is started. The ND control is an engagement control of the forward clutch in the forward / reverse switching mechanism 13, and in a situation where the increase of the engine output is prohibited by the ENG-ECU 62, the actual change rate of the turbine speed is set to the target value. Feedback control is performed as follows. In step T8, the forward clutch is brought into a completely engaged condition,
It is determined whether the ND control has been completed.

In step T8, if the ND control has been completed, the ENG-ECU 62 transmits the ND control in step T9.
Outputs control end signal. When the ENG-ECU 62 receives the ND control end signal from the CVT-ECU 61 in step S9, the ENG-ECU 62 releases the forced idle state of the engine 11 in step S10.

As described above, in the vehicle control device according to the present embodiment, the condition for restarting the engine 11 is satisfied and the ENG
-When the ECU 62 restarts the engine 11, first, C
After the VT-ECU 61 secures the line pressure PL to a predetermined value or more, the ND shift control, that is, the power transmission of the forward clutch is performed. In addition, ENG-ECU 62
The engine 11 is forcibly maintained in the idle state and the required line pressure is maintained at the minimum level until the ND shift control ends. Therefore, the forward clutch is not engaged until the line pressure that can prevent the belt slip is reached.
It is possible to reliably prevent slippage between the belts 41 and 31 and prevent damage to pulleys and belts, thereby improving durability. Further, since the torque input to the CVT is suppressed, the target line pressure decreases, and the time required to reach the target value is shortened. As a result, the shift lever 63 travels from the neutral (N) position. (D) The time required from the start of the engine 11 after the detection of the shift operation to the position to the start of the engine 11 to the start can be shortened, and the start response can be improved.

The present invention is not limited to the above-described embodiment. For example, the stop conditions and restart conditions of the engine 11 may be set according to the vehicle specifications. Although the control when shifting 63 from the neutral (N) position to the traveling (D) position has been described, the control can be similarly performed when shifting to the reverse (R) position to control the reverse brake. Needless to say. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0030]

As described in detail in the above embodiment, according to the vehicle control apparatus of the first aspect, the hydraulic pressure supplied to the control hydraulic device of the belt-type continuously variable transmission reaches a predetermined value. After that, in other words, after the pulley secures the hydraulic pressure necessary to hold the belt, the rotational force of the pulley can be transmitted to the belt, and then the engagement of the hydraulic friction engagement element is started and the engine is started. Is transmitted to the belt-type continuously variable transmission, so that durability can be improved by preventing damage due to slippage between the pulley and the belt.

According to the vehicle control device of the second aspect of the present invention, during the engagement control of the hydraulic friction engagement element, an increase in the output of the engine is prohibited, so that even if there is a high input, The engine output does not increase until the engagement of the hydraulic friction engagement element is completed, the hydraulic pressure required for the belt holding force is reduced, and the response time can be improved by shortening the time until the hydraulic pressure is secured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle control device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a belt-type continuously variable transmission.

FIG. 3 is a flowchart of engine restart control by the vehicle control device;

[Explanation of symbols]

Reference Signs List 11 engine (internal combustion engine) 12 torque converter 13 forward / reverse switching mechanism 14 belt-type continuously variable transmission (CVT) 21 primary pulley 31 secondary pulley 41 belt 50 hydraulic circuit 51 regulator valve 52 gear ratio control valve 61 belt-type continuously variable transmission Electronic circuit unit, CVT
-ECU 62 Electronic circuit unit for engine, ENG-ECU 63 Shift lever

Claims (2)

[Claims] 1. A belt-type continuously variable transmission including a hydraulic friction element which is engaged when the shift lever is in a traveling position and released when the shift lever is in a neutral position, and wherein the shift lever switches from a neutral position to a traveling position. Engine start means for starting an engine when the engine is started, engagement control means for controlling engagement and disengagement of the hydraulic friction engagement element, and the belt type continuously variable transmission when the engine is started by the engine start means Hydraulic pressure determining means for determining whether or not the supply hydraulic pressure to the control hydraulic device is a predetermined value, and engagement of the hydraulic friction engagement element by the engagement control means when the supply hydraulic pressure reaches a predetermined value. And a engagement command means for commanding the start of the vehicle. 2. The vehicle control device according to claim 1, further comprising an output increase inhibiting means for inhibiting an increase in the output of the engine during the engagement control of the hydraulic friction engagement element. Vehicle control device.